最新刊期
卷 44 ， 期 9 ， 2024
- “在材料科学领域，最新研究揭示了热处理对AlSi10MnMg合金性能的显著影响。通过优化工艺，合金的热导率和力学性能均得到显著提升，为高性能铝合金的应用提供了新思路。”摘要：AlSi10MnMg alloy specimens were fabricated by Sr and Ce composite modification combined with squeeze casting， and effects of heat treatment on microstructure and properties of alloy were investigated. The results indicate that the structure become more uniform after heat treatment， where the eutectic Si phase is transformed from worm-like and coral-like to finer particles， and boundary morphology is more spheroidized， with increasing electron transfer efficiency and thermal conductivity. After 540 ℃×0.5 h solid solution treatment， the thermal conductivity attains a maximum of 194.53 W/（m·K）， which is increased by 7.07% compared to that of one with Sr+Ce composite modification. After T6 heat treatment， the thermal conductivity of the alloy tends to decrease due to the partially eutectic Si precipitation and lattice distortion. The overall tensile strength of the alloy is declined with increase in solid solution time， while elongation is increased， and the tensile and yield strength are further enhanced after T6 heat treatment， whereas elongation is decreased considerably due to the precipitation of alloy elements. After 530 ℃×0.5 h solid solution +180 ℃×6 h T6 aging heat treatment， the tensile strength， yield strength and elongation reach 348.26 MPa， 263 MPa and 14.92%， which is enhanced by 52.1%， 205.8% and 2.1% compared to those of ones with Sr+Ce composite modification， respectively.关键词：AlSi10MnMg Aluminum Alloy;Heat Treatment;Thermal Conductivity;Mechanical Properties
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发布时间：2024-09-18 - “在材料科学领域，最新研究揭示了Al-7.5Ni-5Fe-xCo合金的组织演变和热学性能变化。研究发现，随着Co的加入，合金的组织结构得到细化，热导率和热膨胀系数降低，为高性能合金开发提供新思路。”摘要：Al-7.5Ni-5Fe-xCo（x=0，0.3，0.6，1，2，%） alloys were prepared by permanent mold casting， and the evolution of microstructure and thermal properties were systematically investigated. The results indicate that the primary Al9FeNi phase is refined， and the volume fraction of eutectic structure around the primary phase is gradually increased after Co addition. Co exists in the form of solution atom of Al9FeNi phase in Al-7.5Ni-5Fe alloy， which is easy to replace Ni elements in Al9FeN to form Al9M2（M=Fe， Ni and Co） phase due to the greater activity. Solidification heat analysis confirms that the precipitation solidification temperature of Al9FeNi phase is advanced after Co addition， while the precipitation temperature of Al13Fe4 phase is decreased. The solid diffusion reaction at initial stage of solidification is reduced， and the transformation of solidification process leads to the refinement of microstructure. With the addition of Co， the thermal conductivity and thermal expansion coefficient of the alloy are decreased to a certain extent， which is mainly attributed to the solid solution of Co atom in Al9FeNi phase.关键词：Al-Fe-Ni Alloys;Thermal Conductivity;Thermal Expansion;Modification
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发布时间：2024-09-18 - “在材料科学领域，研究人员通过搅拌铸造法制备了AlN/ZC55复合材料，发现AlN的添加能显著降低热膨胀系数，同时对散热性能有轻微影响。”摘要：Mg matrix encapsulation materials possess the advantage of low density and high electromagnetic shielding， while the excessively high coefficient of thermal expansion limits their usage. As a new type of substrate material， AlN exhibits a higher thermal conductivity and a lower coefficient of thermal expansion （CTE） than those of magnesium alloys， which can be used as a reinforcement phase to improve the thermophysical properties of magnesium alloy. AlN/ZC55 composites were prepared by stirring casting method， and the influence of AlN content on thermophysical properties of composites was explored. The results indicate that AlN particles can significantly reduce the CTE and slightly weaken the heat dissipation performance of composite. With 20% of AlN particles addition， the thermal conductivity reaches 126.2 W/（m·K） while CTE is 1.983×10-5 K-1.关键词：Magnesium Matrix Composites;Thermal Conductivity;Coefficient of Thermal Expansion;AlN
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发布时间：2024-09-18 - “在材料科学领域，最新研究揭示了铒元素对AlSi10Mg合金微观结构和性能的积极影响，通过细化晶粒和变质共晶硅，显著提升了合金的热导率。”摘要：The influence of rare earth Er on microstructure and properties of AlSi10Mg alloy was investigated using metallographic microscopy， scanning electron microscopy， electron probe， hardness testing， and conductivity testing， and the influence law and mechanism were analyzed. The results indicate that the addition of rare earth Er can promote the refinement of α-Al grain and modification of eutectic Si in the alloy. With the increase of Er content， the microhardness is slightly improved. When Er content is less than 0.6%， the thermal conductivity is increased with the Er content. With 0.6%Er addition， the thermal conductivity reaches the peak value of 151.89 W/（m·K）. With the further increase of Er， the thermal conductivity is decreased slightly. The addition of rare earth Er can improve the thermal conductivity of alloy by reducing solid solubility of solute elements in the matrix and modifying eutectic Si.关键词：AlSi10Mg Alloy;Rare Earth Er;Thermal Conductivity
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发布时间：2024-09-18 - “在铝合金材料研究领域，专家通过添加Sb对Al-7Si-0.4Mg-0.4Cu合金进行变质处理，显著改善了合金的微观结构和性能。”摘要：Al-7Si-0.4Mg-0.4Cu alloy was modified by adding Sb， and effects of microstructure， thermal conductivity and mechanical properties of alloys with different Sb contents were investigated. The results indicate that morphology of eutectic Si in the alloy is improved and eutectic Si is refined after Sb addition under the metal mold casting. In addition， Sb can refine the secondary dendrite spacing of α-Al， thus improving the thermal conductivity and mechanical properties of alloy. The modification effect presents desirable with 0.2% Sb， where the secondary dendrite spacing， average length and width of eutectic Si are decreased by 63.78%， 60.92% and 54.42%， respectively. The thermal conductivity， tensile strength and elongation of modified alloy reach 149.56 W/（m·K）， 234.56 MPa and 8.86%， which are increased by 8.49%， 35.66% and 257.26%， respectively， compared with those of unmodified alloy.关键词：Al-Si-Mg-Cu Alloy;Sb Modification;Thermal Conductivity;Mechanical Properties
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发布时间：2024-09-18
Topic·High Thermal Conductivity Alloy
- “在铝合金材料研究领域，专家通过形变热处理技术，优化了7075铝合金线材的组织性能，为提高材料强度和塑性提供了新思路。”摘要：Microstructure and properties of 7075 aluminum alloy wire prepared by continuous rheological extrusion were controlled by thermomechanical treatment. Effects of processes on microstructure and properties of 7075 aluminum alloy wire by continuous rheological extrusion were investigated by metallographic microscope， scanning electron microscope and X-ray diffractometer. The results indicate that the second phase on Al matrix is gradually decreased after solution treatment at 470 ℃ for 90 min， and a small amount of θ phase is distributed at the grain boundaries. With the increase of section reduction， the second phase is dispersed on the Al matrix， and η phase is continuously precipitated with white elongated dispersion. The two-stage aging treatment of 120 ℃×4 h+160 ℃×13 h was carried out on the wire with the diameter of wire reaching 4 mm， and the drawing continued， until the diameter of wire reaches 3 mm， where the elongation is reduced slightly， and tensile strength reaches 530.95 MPa.关键词：Continuous Rheological Extrusion;Thermomechanical treatment;Microstructure and Properties
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发布时间：2024-09-18
Experimental Investigation
- “在铸造工艺领域，受控扩散凝固技术取得新进展，有效细化合金组织，抑制热裂，为铝合金铸件近净成形提供新方案。”摘要：It is crucial to use casting process to form alloy system with large liquid-solid interval to refine the primary structure effectively and inhibit thermal cracking. In contrast to conventional solidification， Controlled diffusion solidification （CDS） can effectively solve the problem of thermal cracking during the near-net-shape casting of deformed aluminum alloys and simplify the process to provide the possibility of industrial application. The research progress in CDS process mechanism was reviewed， and the key events were summarized including mixing， redistribution of temperature and solute fields， three types of nucleation， and influence of process parameters such as precursor alloy temperature， initial mass ratio and mixing rate on the non-dendritic conversion rate of CDS were concluded. Finally， the problems exsiting in CDS solidification and regulation mechanism were presented， and the future development direction was prospected.关键词：Controlled Diffusion Solidification;Solidification Process Control;Near-net-shape Casting;Non-dendritic Conversion
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发布时间：2024-09-18 - “Ni-Cu合金涂层研究取得新进展，优化制备工艺提升性能，为材料应用提供新方向。”摘要：The research progress in Ni-Cu wear-resistant and corrosion-resistant alloy coatings was reviewed. Preparation process includes electrodeposition， spraying， laser cladding and other methods， and performance characterization mainly involves microstructure， characteristics， hardness， wear resistance and corrosion resistance of coating. The enhancement of properties could be achieved by optimizing preparation process， adjusting composition and improving microstructure of coating. The research hotspot and development trend of Ni-Cu wear-resistant and corrosion-resistant alloy coatings were summarized， aiming to provide reference for further research and application.关键词：Ni-Cu Alloy;Coating;Microhardness;Wear Resistance;Corrosion Resistance
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发布时间：2024-09-18
Research·Review
- “在材料科学领域，研究人员通过数值分析建模，深入探究了电弧预热对铝合金涂覆沉积层温度变化及形貌的影响，为提高沉积层质量提供了新思路。”摘要：In order to explore the internal temperature variation of aluminum alloy coated sedimentary layer by arc preheating and influence of arc preheating parameters on deposition morphology， the evolution process of temperature field of aluminum alloy coated components was investigated by numerical analysis and modeling， and the numerical calculation model was verified by experiments. The results indicate that the heat input of preheating arc is one of the main factors affecting the morphology evolution and surface quality of sedimentary layer during solidification process. The mushy area in the cross-section of sedimentary layer is concave in the middle and convex on both sides before 0.1 s due to the high-temperature fuse. Moreover， the melt spreads out fully on the substrate with the peak current increasing to 200 A， leading to satisfied morphology of sedimentary layer. The substrate undergoes a secondary heating process， and the closer to the upper surface of substrate， the greater the maximum temperature difference， where the maximum temperature difference reaches 250 K.关键词：Fused Coating;Temperature Field;Arc Preheating;Aluminum Alloy
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发布时间：2024-09-18 - “在提升挤压铸造设备性能领域，专家采用多目标优化方法，通过数学模型和仿真验证，显著提高了合模机构的运动和力学性能。”摘要：In order to improve the motion and mechanical performance of the clamping unit of squeezing casting equipment， a multi-objective optimization method was proposed based on the Coordination Curve Method and Layered Sequential Method. Firstly， the operational characteristics of the curved lever-type die-closing mechanism in squeezing casting equipment were analyzed， and a mathematical optimization model was constructed. Subsequently， the harmonious correlation between stroke ratio and force ratio was established， and the tolerance values were assigned for optimization objectives. The penalty function algorithm was used to optimize the multi-scheme optimization of the targets such as force increase ratio， stroke ratio， speed ratio and member mass sum of the clamping unit， and the most suitable optimization scheme was selected. ADAMS software was leveraged for the construction of a virtual prototype model， enabling precise simulation and validation of motion. Finally， the on-site experimental platform was established for the evaluation of motion characteristics and mechanical properties， providing experimental validation for the mathematical model and simulation results. The results reveal a notable 14.4% increase in force ratio， a 6.9% enhancement in stroke ratio， and a marginal reduction in the total mass of rods compared to the pre-optimization state. The speed and acceleration performance of the moving plate are greatly improved.关键词：Squeeze Casting Equipment;Clamping Unit;Multi-objective Optimization;Coordination Curve Method;Tolerance Hierarchical Sequence Method
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发布时间：2024-09-18 - “在增材制造领域，研究人员采用激光选区熔化技术制造了含复杂流道的燃烧室模拟件，并利用CR和CT技术检测内部多余物。结果显示，CR能检出最小0.15mm凸出立方体和0.1mm线形多余物；显微CT能检出最小0.08mm凸出立方体和0.1mm线形多余物。”摘要：A combustion chamber simulator with complex channels was manufactured by selective laser melting technique. Convex cubic residues with different sizes were prefabricated in the channels， and a set of standard size metal wires were placed to simulate linear residues. Computed radiology （CR） and microscopic computed tomography （CT） were utilized to investigate the detection capability of X-ray imaging method for residues in the internal channels of additive parts， and the wall thickness of channel was analyzed and evaluated by micro-CT. The results indicate that CR can detect the convex cubic residues with a minimum size of 0.15 mm and linear residues with a minimum diameter of 0.1 mm， while micro-CT can detect the convex cubic residues with a minimum size of 0.08 mm and linear residues with a minimum diameter of 0.1 mm. The measurement sizes of linear residues are consistent with standard size， while that of convex cubic residues are generally larger than the designed sizes with the maximum absolute error less than 50 μm. Moreover， the wide-section channels exhibit desirable uniformity by micro-CT.关键词：Selective Laser Melting;Micro Computed Tomography;Computed Radiology;Residue;Channel
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发布时间：2024-09-18 - “在材料科学领域，专家通过有限元分析和元胞自动机法，优化了锡磷青铜水平连铸工艺，有效改善了铸坯组织不均匀问题，为提高材料性能提供了新方案。”摘要：During horizontal continuous casting of tin-phosphor bronze， the excessive cooling at the edges results in uneven transverse microstructure of billet， thus negatively affecting subsequent rolling forming processes and properties of strip products. An air groove structure was set up on the surface of graphite mold to achieve appropriate increase in thermal resistance at the edge， ensuring similar cooling strength between edges and core of billet. An accurate model for horizontal continuous casting crystallizer was established by finite element software and temperature field analysis was conducted. The cellular automaton method was employed to compute the microstructure of billet before and after optimization， and parameters of air groove size on the mold surface were optimized by orthogonal experiments. The optimal dimensions of air groove are determined as length of 115 mm， width of 45 mm， and depth of 1 mm. Industrial testing verifies that the arc area of surface crystallization line of casting billet with air groove is reduced by 46 mm， the transverse temperature difference is reduced by 20.23 ℃， and the range of differentiated solidified structure at the edge is reduced by 27 mm.关键词：Tin-phosphor Bronze;Air Groove;Orthogonal Experiment;Transverse Temperature Difference;Solidification Microstructure
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发布时间：2024-09-18
Research·Computer Application
- “在增材制造领域，研究者基于ABAQUS和FE-SAFE建立了Ti-6Al-4V合金孔隙模型，发现球形孔隙对疲劳寿命影响较小，孔隙率和孔隙大小是关键因素。”摘要：Taking Ti-6Al-4V alloy as object， the model for shape， location， size， mutual distance， number and porosity of pore defects during additive manufacturing process was established by ABAQUS and FE-SAFE， and effects of pore defects on the fatigue life of SLMed Ti-6Al-4V alloy specimens were investigated. The results indicate that the influence of spherical pores on fatigue life is lower than non-spherical pores. In range of 10~30 μm， influence of spherical internal pore defects on fatigue life is more significant. In range of 40~70 μm， influence of surface pore defects on fatigue life is more obvious than internal pore defects. The rangeability in fatigue life of specimen is increased with increase in radius of spherical pore defect when the porosity is less than 1%. The fatigue life of specimens with mixed pore defects reaches the minimum value with porosity of 1%~5%. The fatigue life fluctuates in a range with different random arrangements.关键词：Selective Laser Melting;Ti-6Al-4V Alloy;FE-SAFE;Pore Defect;Fatigue Life Analysis
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发布时间：2024-09-18
Research·Additive Manufacture
- “在铸造稀土镁合金领域，研究者通过压力调控固溶处理，有效平衡了合金元素固溶与晶粒长大问题，为提升合金强塑性提供了新思路。”摘要：In view of the contradiction between sufficient solid solution of alloying elements and grain growth， the effects of pressure on solid solution process of alloying elements were investigated. The microstructure and mechanical properties of Mg-14Gd-1Zn-0.4Zr alloy after vacuum and atmospheric solution treatment as well as the mechanical properties of alloys in peak-aging state were analyzed. The influence mechanism of pressure on atomic solution process was described. The results indicate that the microstructure of as-cast Mg-14Gd-1Zn-0.4Zr alloy is mainly composed of α-Mg， （Mg，Zn）3Gd， 14H LPSO phases. After solution treatment at 480 ℃×20 h at normal pressure， LPSO phase disappears and a small amount of （Mg，Zn）3Gd remains. After solution treatment at 500 ℃×20 h at normal pressure and 480 ℃×20 h at vacuum conditions， LPSO phase disappears and absence of residual （Mg，Zn）3Gd phase can be observed， however the grain size is coarsened slightly under vacuum condition， and the strength and plasticity are increased. The peak aging time of both alloys at 225 ℃ is 24 h， and the tensile strength and elongation of the latter are significantly improved， with the tensile strength of （360.5±1.2） MPa， yield strength of （234.6±0.8） MPa， and elongation of （5.2±0.3）%. When the pressure is reduced to vacuum， the diffusion coefficient of atoms is increased and the solution efficiency is improved. Solid solution of Gd and Zn atoms can be achieved at a lower solution temperature， and the grain growth is retarded， thus improving overall strength and toughness.关键词：Pressure;Solution Treatment;Mg-14Gd-1Zn-0.4 Zr Alloy;Mechanical Properties
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发布时间：2024-09-18 -
Impact Analysis of Titanium Alloy Blank Folded Layer by Electron Beam Cold Bed Furnace Smelting AI导读
“在电子束熔铸技术领域，研究揭示了铸锭表面折层与电子枪功率及液位的关联，为提高熔铸效率和质量提供了新见解。”摘要：The relationship between the folded layer of blank surface of ingots with different dimensions and power or liquid level of electron gun in the 3 200 kW electron beam cold bed furnace smelting was investigated， and formation mechanism of folded layer was clarified. The results indicate that with the constant power， the folded layer amounts at non-overflow side of the blank are increased with the increase of liquid level. Under the common liquid level， the power of electron gun is increased and the folded layer is reduced. During the melting of crystallizer with 1 080 mm， the power of electron gun on liquid surface is （350±10） kW， and the blank is less folded and the energy consumption is the lowest when the liquid level is equal to overflow mouth. During the melting of crystallizer with 1 280 mm， the power of electron gun on liquid surface is （380±10） kW， and the blank is less folded and the casting energy consumption is the lowest when the liquid level is equal to overflow mouth. The increase in the width of the mold ensures a decrease in the power density of the electron gun with less folding.关键词：Crystallizer;Titanium Alloy;Electron Beam Cold Bed Furnace- 2
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发布时间：2024-09-18
Research·Alloy Process
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Effects of AlN-CrFe Mixed Components on Properties of Cu-based Powder Metallurgy Friction Materials AI导读
“在铜基摩擦材料研究领域，科学家们采用粉末冶金技术，通过调整AlN-CrFe混合摩擦组元比例，成功优化了材料性能。研究发现，AlN含量的增加能显著提升材料硬度，同时降低密度，而当AlN含量超过9%后，性能变化趋于稳定。此外，随着AlN含量的提高，摩擦因数和相对磨损量均有所下降，当AlN与CrFe的比例达到3∶9时，材料展现出较大的摩擦因数和良好的稳定性。磨损机理分析显示，随着AlN含量的增加，材料表面的磨损特征由剥层磨损逐渐转变为氧化磨损，最终演变为磨粒磨损，这为铜基摩擦材料的进一步研究和应用提供了重要参考。”摘要：Taking AlN-CrFe as mixed friction component， Cu-based friction materials were prepared by powder metallurgy method， and effects of AlN-CrFe content on properties of Cu-based friction materials were investigated. The results indicate that with the gradual increase in AlN content， the hardness is gradually increased， while the density shows a gradual decline trend. When AlN content exceeds 9%， the variation of hardness and density of material is indistinctive. Both the friction coefficient and relative wear amount are gradually reduced with the increase of AlN content. A high and stable friction coefficient can be obtained with the AlN/CrFe proportion of 3∶9. During the friction and wear test， there exist spalling pits and cracks on the surface of material， which become smaller with the AlN content increasing. The wear mechanism is gradually transformed from peeling wear to oxidizing wear， and finally to abrasive wear.关键词：Cu-based Friction Material;Powder Metallurgy;Property;Friction Component- 2
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发布时间：2024-09-18 - “在材料科学领域，研究者基于密度泛函理论，深入探讨了无序Al1-xLix合金的力学性能。发现Al1-xLix合金在0 K时能形成稳定结构，但Al0.75Li0.25相较难形成。随着Li含量增加，FCC相由韧性向脆性转变，BCC相表现出显著各向异性，而FCC相趋向各向同性。这些发现为合金设计提供了新思路。”摘要：Effects of different structures on the elastic modulus， anisotropy and ideal tensile strength of disordered Al1-xLix （x=0.25，0.5 and 0.75） were investigated based on density functional theory. The results indicate that the Al1-xLix phase leads to a stable structure at 0 K， while the formation of Al0.75Li0.25 phase is difficult. For the Al1-xLix phase with constant composition， BCC structure exhibits a relatively weak resistance to volume deformation. With molar fraction of Li increasing from 50% to 75%， FCC Al1-xLix phase undergoes a ductile-brittle transition， which is attributed to the transformation from metallic bonds to directional covalent bonds. The elastic properties of BCC Al0.75Li0.25 exhibit significant anisotropy， while FCC Al0.75Li0.25 and BCC Al0.25Li0.75 tend to be isotropic. With the increase of Li content， the ideal tensile strength of Al1-xLix phases with the same structure is decreased.关键词：First Principles;Al1-xLix Phase;Elastic Properties;Anisotropy
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发布时间：2024-09-18 - “在铝合金凝固组织和力学性能研究领域，专家通过施加不同频率脉冲磁场，发现40 Hz频率下合金晶粒最细化，显著提升力学性能，为铝合金材料优化提供新思路。”摘要：The impact of pulsed magnetic fields with different excitation frequencies （0， 20， 40 and 50 Hz） on solidification structure and mechanical properties of ZL205A aluminum alloy melt was investigated. Optical microscopy （OM） and field emission scanning electron microscopy （FESEM） were employed to analyze solidification structure. The results indicate that the pulsed magnetic field can significantly refine grain size in the alloy， and coarse network-like
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发布时间：2024-09-18 - “在材料科学领域，研究人员通过CALPHAD方法计算了Cu-Ni-Si、Cu-Zn-Al三元体系相图，确定了镍硅黄铜合金成分。调控Cu-36Zn-7Ni-2Si-xAl合金中Al含量，揭示了合金基体相变及Ni2Si增强相分布规律，为合金设计提供新思路。”摘要：The ternary system phase diagrams of Cu-Ni-Si， Cu-Zn-Al as well as pseudo binary phase diagrams were obtained based on CALPHAD method to determine the composition of nickel-silicon brass with composite structure of hard β matrix+Ni2Si reinforcement phase. By adjusting Al content in Cu-36Zn-7Ni-2Si-xAl （mass fraction， %） alloy， it is found that when the Al content exceeds 1%， the alloy matrix （α+β） is transformed to single β phase. Meanwhile， the Ni2Si reinforcement phase distributed in the matrix exhibits continuous coral like （eutectic Ni2Si） and dispersed granular （primary Ni2Si） morphologies. With Al content increasing， the proportion of eutectic Ni2Si is firstly increased slightly and then decreased significantly， which approaches 0 when Al content reaches 3%.关键词：CALPHAD;Nickel-silicon Brass;Microstructure Evolution;Ni2Si Reinforcement Phase
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发布时间：2024-09-18 - “在腐蚀性溶液中，非晶合金表现出优异的抗腐蚀性能，尤其是Hf28合金在含Cl-环境中腐蚀程度最低，为材料科学领域提供了新的研究方向。”摘要：Electrochemical corrosion behaviors of Hf28Be18Ti17Zr17Cu7.5Ni12.5， Zr41.2Ti13.8Cu12.5Ni10Be22.5， and （Cu43Zr48Al9）98Y2 amorphous alloys in 3.5% NaCl solution，1 mol/L HCl solution， and 1 mol/L H2SO4 solution were investigated， and compared with 304 stainless steel. The results reveal that in Cl- containing etchant， significant corrosion occurs in all amorphous alloys， where the corrosion degree and corrosion current density of Hf28 alloy are the lowest， while Cu-based amorphous alloys undergo severe corrosion. In 1 mol/L H2SO4 solution， all amorphous alloys exhibit desirable corrosion resistance， with corrosion current densities around 10-7A/cm2 and positive corrosion potentials. Absence of corrosion trace was observed on the surfaces of alloys， indicating strong impact of Cl- on amorphous alloys， and passivation films were easily formed in oxidizing etchant， proving excellent corrosion resistance of amorphous alloys.关键词：Amorphous Alloys;Electrochemical Corrosion;Corrosion Current Density
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发布时间：2024-09-18 - “在材料科学领域，研究者通过热处理优化了低铜含量铸造Al-Si-Mg-Cu合金的性能，发现固溶和时效处理显著影响合金的强度和塑性，为合金应用提供了新思路。”摘要：The effects of heat treatment on microstructure and properties of cast Al-Si-Mg-Cu alloy with low Cu content were investigated by means of optical microscope， SEM and tensile test. The results indicate that the strength and elongation of alloy are increased firstly and then decreased with the extension of solution time， and the eutectic silicon morphology tends to spheroidized. With the extension of aging time at 150 ℃， the strength of alloy is gradually increased， and tensile strength reaches 339.87 MPa after aging for 14 h， while elongation presents a trend of decreasing first， and then increasing finally decreasing. At 165 ℃， the strength is increased firstly and then decreased with the aging time， which reaches a peak value at 10~14 h， while the elongation is decreased continuously. After heat treatment， W-Al2Cu5Si4Mg4 and Mg2Si phases are precipitated， which are dispersed in the matrix， leading to the second phase strengthening and dispersion strengthening， which can improve the strength of alloy and reduce the plasticity toughness.关键词：Al-Si-Mg-Cu Alloy;Solution Treatment;Aging Treatment;Microstructure;Mechanical Properties
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发布时间：2024-09-18 - “在铝合金领域，研究者通过添加稀土La和Al-5Ti-1B，显著提升了A356合金的力学性能，为材料科学的发展提供了新思路。”摘要：The effects of rare earth La and Al-5Ti-1B addition on the microstructure of primary α-Al， eutectic Si phase and tensile properties of A356 casting aluminum alloy were investigated. The results indicate that rare earth La and Al-5Ti-1B addition exhibits a multi-refining effect on the microstructure of A356 alloy， including refinement of α-Al grains and the decrease of secondary dendrite arm spacing as well as the transformation of eutectic Si morphology from plate-like to small granular and rod-like. Due to the refinement of α-Al grains and the improvement of the microstructure of eutectic silicon fibers， the tensile strength， yield strength， and elongation of A356 aluminum alloy treated with 0.3% La+0.15% Al-5Ti-1B refiner are increased by 35%， 33%， and 400%， respectively， which far exceeds the performance of traditionally treated ones. After T6 heat treatment， the tensile strength， yield strength， and elongation of refined A356 aluminum alloy are increased by 24%， 20%， and 176%， respectively， compared to those of ones without refinement treatment.关键词：Rare Earth La;Al-5Ti-1B;Refinement;Modification;Mechanical Properties
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发布时间：2024-09-18 - “在材料科学领域，研究人员建立了基于经验参数的高熵合金室温屈服强度预测模型，为合金性能预测提供新方法。”摘要：A method to predict the room temperature yield strength of HEA was proposed based on empirical parameters. Taking empirical parameters as input variables， a multivariate linear regression model was constructed， which performed well in terms of goodness-of-fit （R2） at 0.996. Meanwhile， the average error of predicted yield strength is only 4.2%. Moreover， the empirical parameters exhibiting the most significant influence on yield strength were identified through Pearson’s correlation coefficient test， including valence electron concentration， theoretical melting point， mixing enthalpy and entropy-enthalpy ratio.关键词：Empirical Parameters;Multiple Linear Regression Models;HEA;Pearson's Correlation Coefficient
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发布时间：2024-09-18
Research·Alloy Performance
- “在铝合金盖板铸造工艺领域，专家通过AnyCasting软件仿真分析，揭示了密封槽缺陷成因并提出改进措施，显著提升了铸件合格率。”摘要：With the help of AnyCasting software， the filling and solidification simulation analysis of permanent mold low-pressure casting process of aluminum alloy cover plate for GIS was carried out to understand the origination of casting defects in cover plate sealing groove， and optimized measures were provided. Finally， production validation was conducted. The results indicate that when the mold temperature is set at the lower limit and the upper limit for the working temperature， absence of shrinkage and porosity defects on the flange surface is observed according to the filling and solidification simulation analysis of the original process. The cover plate has a sealing groove defect， which is directly relevant with poor exhaust from the risers and the actual pouring inadequate height of the risers. The actual pouring height of the flange insulation riser is less than 1.24 times of the flange thickness， which has difficulty in effectively feeding the flange， resulting in shrinkage and porosity defects in cover plate sealing groove. Through optimizing designed scheme， the actual pouring height of the flange insulation riser is more than 1.55 times of flange thickness， and the qualified rate of the castings is over 99%. The simulation results are consistent with the actual ones关键词：GIS;Cover Plate;Filling and Solidification;Process Optimization;Low Pressure Casting
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发布时间：2024-09-18
Application·Die Casting
- “在铸造技术领域，专家通过优化浇注系统设计，显著提升了ZM6格栅铸件的充型效果和凝固质量，为批量生产提供了有效方案。”摘要：The hydraulic principle of gating system design was adopted and gating system of ZM6 grid castings was optimized by low-pressure casting with vertical gap runner. The liquid flow and temperature field distribution during the pouring process were simulated and analyzed by ProCAST software. The results indicate that using hydraulic principles， increasing the contact area between the gap runner and the casting， as well as the number of vertical cylinders， the filling effect can be significantly improved and the temperature gradient at various points of the casting during the solidification process was reduced. The optimized gating system design was adopted to achieve the formation of grid castings combined with specialized grinding heads for post casting repair， meeting the requirements of quantity production of grid castings.关键词：Grid;Magnesium Alloy;Low Pressure Casting;Gating System Design;Numerical Simulation
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发布时间：2024-09-18 - “在精密铸造领域，专家通过正交试验优化车钩铸造工艺，确保了组织致密性和性能达标，为提高铸造质量提供了有效方案。”摘要：In order to prevent cracks from forming in investment casting couplers and obtain dense microstructure and desirable performance， the optimum parameters for simulation orthogonal test of investment casting were determined as follows： pouring temperature of 1 570 ℃， preheating temperature of 425 ℃ and pouring time of 29 s. The influence of casting temperature field and stress field on formation of shrinkage porosity and crack under optimal parameters was analyzed through casting simulation. Meanwhile， key parts of castings were simulated by KGT model. Absence of internal cracks and pores is observed by X-ray detection， and the microstructure of corresponding parts is basically consistent with simulated ones. The average tensile strength of coupler after heat treatment can reach 1 020 MPa. The results indicate that the casting parameters are reasonable after orthogonal optimization， and the grain is fine， of which the performance exceeds the railway standard requirements.关键词：Locomotive Coupler;Investment Casting;Stress;Microstructure Simulation;Mechanical Properties
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发布时间：2024-09-18
Application·Investment Casting
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