最新刊期
卷 ， 期 2 ， 2008
- 摘要：The(Cu50Zr42Al8)99Cr1 and(Cu50Zr42Al8)99Ni1 amorphous alloy rods with 3.0 mm in diameter whose friction and wear properties were tested with the pin-on-disc friction tester were prepared by suction casting with copper mold.The results indicate that the friction behavior at low velocity and the sliding speed of abrasive wear of（Cu50Zr42Al8）99Cr1 amorphous alloy rods are significantly improved by adding Cr element,while the friction behavior at low speed is also obviously improved,however,it has been little improved at high speed by adding Ni.关键词：Bulk Amorphous Alloy;Friction and Wear Properties;Wear Mechanism
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- 214
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发布时间：2023-12-18 - 摘要：The effects of heating temperature on the microstructure of grain-refined AZ91D magnesium alloy billets heated at 580,600 and 620 ℃ have been observed by optical microscope.The results indicate that the higher the heating temperature is,the faster the remelting rate of the billets is and the finer the grain size is.The improvement of heating temperature can promote the remelting rate and restrain the coalescence of grains to a certain extent,which is helpful to refining the grain size in partial remelting structure.关键词：AZ91D Magnesium Alloy;Partial Remelting;Microstructural Evolution
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- 158
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发布时间：2023-12-18 - 摘要：The compression test of as-cast lead brass was conducted by thermal/mechanical simulating testing machine,Gleeble-1500D,with the strain rate of 0.000 20.00 5 s-1 at 540660 ℃ and the initial grain size of 38 μm and true strain at 0.11.2.Based on the Sellars model,the model of dynamic recystallization（DRX） has been established by experimental data regression,and then the DRX in the solid cages during quasi-superplastic extruding process has been simulated by Deform-3D software,which is well in agreement with the practical ones,showing the availability of the established model.关键词：As-cast Lead Brass;Dynamic Recrystallization;Dynamic Recrystallization Model;Quasi-superplasticity
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- 299
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发布时间：2023-12-18 - 摘要：The surface morphology,macro-micro-hardness and compressive behavior of Ti47Al rectangular billets prepared by continuous melting and solidification with cold crucible have been investigated.The results indicate that the surface morphology of the rectangular billet is affected by electromagnetic force.The columnar crystal that is parallel to growth direction can be generated in the microstructure of the billets after a section of equiaxed or lathy grains,however,the undirectional equiaxed grain section can be observed in the outer-side of the billets.The directional structure in the billets consists of the lamellar structure that is parallel or nearby 45 °to the pulling direction.In addition,the microstructure of the billets is consistent with the surface color.The compressive testing reveals that the compressive strength of the billet at direction solidification region is superior to that of the other region ones.关键词：Cold Crucible;Continuous Casting;Directional Solidification;TiAl Alloy
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- 228
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发布时间：2023-12-18 - 摘要：The micro-hardness,electric conductivity and tensile strength of Cu-2.32Ni-0.57Si-0.05P alloy with different cold deformations after varied aging treatments have been measured,and the precipitates in the alloy have been observed by TEM and SEM.The results show that the comprehensive properties of the alloy can be greatly improved with cold deformation and aging treatment.The desirable comprehensive properties of the different cold deformed alloy can be observed with aging at 450 ℃ after solid solution at 900 ℃ for one hour.The micro-hardness and electric conductivity of 80% cold deformed alloy can reach 240 HV and 23.78 MS/m,respectively,with aging at 450 ℃ for one hour,while the tensile strength of the 40% cold deformed alloy can reach 568 MPa with aging at 450℃ for one hour.The dispersively distributed δ-Ni2Si phase with fine grain size can be precipitated from the alloy during aging treatment,which is gradually grown with extending aging time.关键词：Cu-2.32Ni-0.57Si-0.05P Alloy;Micro-Hardness;Electric Conductivity;Aging
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发布时间：2023-12-18 - 摘要：The effects of cooling rate and Ce addition on the growth behavior,appearance,characteristics and numbers of the divorced eutectic β phase in microstructure of the AZ31 magnesium alloy have been analyzed.The results reveal that Ce addition can greatly influence the microstructure of the alloy.The divorced eutectic β phase in the AZ31 magnesium alloy is converted from continuous net-like structure into discontinuous short rod or particle with the Ce addition increasing to 0.6%,and its amounts are decreased with the declination of cooling rate.In addition,Mg-Al-Zn-Ce compound can be observed in the alloy.关键词：Magnesium Alloy;Divorced Eutectic Phase;Cooling Rate;Ce Element
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- 348
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发布时间：2023-12-18 - 摘要：The thermo-dynamics and crystal growth of in-situ synthesized TiB2 reinforcement were investigated in A356 Al/K2TiF6 +KBF4 mixed salt reaction system.The results indicate that the in-situ reaction temperature has affected significantly the final product in the system and morphology of TiB2 reinforcement.The TiAl3 phase in the composites can be totally disappeared and six-rowed granular TiB2 reinforcement can be generated with controlling reaction temperature of A356 Al/K2TiF6 +KBF4 mixed salt reaction system at 850 ℃,which is beneficial to improving the enhancing effects.关键词：Aluminum Matrix Composites;In-situ Sythesization;TiB2;Crystal Growth
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- 486
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发布时间：2023-12-18 -
Morphology and Phase Constituent of Secondary Phase in As-cast Microstructure of 7150 Aluminum Alloy
摘要：The as-cast microstructure of 7150 aluminum alloy was observed by OM（optical microscope） and SEM（scanning electron microscope）,XRD（X-ray diffractometer）,in which the second phase was analyzed by EDS（energy dispersive spectrometer）.The results reveal that the as-cast microstructure of 7150 aluminum alloy is composed of MgZn2（η phase）,Al2CuMg（S phase）,Al2Mg3Zn3（T phase）,primary Al phase,Mg2Si phase and Al6（FeCu） phase.The EDS observation shows that the η phase and T phase is dissolved into Cu element,while S phase is dissolved into Zn element.In addition,the Zn and Mg element content in T phase are slightly higher than that of in S phase.关键词：7150 Aluminum Alloy;As-cast Microstructure;Secondary Phase;Al2CuMg（S Phase）;Al2Mg3Zn3（T Phase）- 2
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发布时间：2023-12-18 - 摘要：The flow stress model of AZ80 magnesium alloy has been established to determine the optimal processing parameters of AZ80 magnesium at elevated temperature and to obtain the factors influencing deformation variables by observing the rheological behavior of the alloy.The results reveal that there exists stress peak and deformed softening characteristics in AZ80 magnesium,in which the flow stress would keep a stable value with the strain more than 0.3.The optimal processing parameters can be obtained with strain rate of 10 s-1 at 370 ℃ in the processing map.The uniform and fine dynamic recrystallized equaixed grain is dominant in the microstructure of the AZ80 wrought alloy,exhibiting excellent mechanical properties.关键词：AZ80 Magnesium Alloy;Plasticity;Flow Stress Model
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- 330
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发布时间：2023-12-18 - 摘要：The tendency and direction of crack formation in the round ingot is closely dependent on the casting speed in semi-continuous casting.The coupled thermal-stress finite element model for semi-continuous casting 7050 aluminum alloy billets has been established based on MSC.marc software,in which the hexahedral element type with eight nodes is adopted and the influence of liquid-solid transformation and solidification latent heat are considered.The effects of different casting speeds on temperature field and stress field in semi-continuous casting have been simulated with determining the complicated boundary confined condition.The simulated results indicate that the decrease of casting speed can reduce the gradient of cooling rate between inner and outer of the ingot to decrease the tensile stress in ingot surface,which is helpful for promoting the formation of the ingot and relieving the tendency of crack formation.关键词：7050 Aluminum Alloy;Semi-continuous Casting;Round Ingot;Hot Crack;Numerical Simulation
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- 457
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发布时间：2023-12-18 - 摘要：The filling behavior of an automobile component in lost foam casting was simulated by the Procast software,and the difference of filling behavior between in lost foam casting and in common casting was described.The simulated results indicate that there exists sharp difference for filling process in lost foam casting and in common casting,in which the filling process needs a longer time as a result of the existence of the foam pattern restraining the filling of liquid metal,and the filling rate exhibits alternative change.关键词：Lost Foam Casting;Numerical Simulation;Filling Behavior;Filling Rate
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- 340
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发布时间：2023-12-18 -
- 摘要：A new rheo-forming method in which the slurry preparation was independent on the component forming was developed by integrating LSPSF（low shearing pouring semi-solid fabrication） with direct squeezing forming method.The rheo-squeezing forming was conducted successfully for aluminum alloy cannonball shells（thin-walled and deep-cylinder parts） using YB32-300 hydraulic presser.The results indicate that the new rheo-squeezing forming system has the features of simple operation and excellent slurry formability,which is beneficial to forming the parts with desirable surface quality due to realize the quantitative pouring and slurry delivery.The microstructure of parts in different position is different due to the uneven pressure distribution on semi-solid slurry.There exists more spherical phase in center and less spherical phase as well as more liquid phase near to the edge of inner surface of the parts on the transverse section.However,the microstructure in the bottom is the same as that of semi-solid before rheo-squeezing casting.关键词：Rheo-forming;Slurry Preparation;Squeezing Casting;Microstructure
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- 600
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发布时间：2023-12-18 - 摘要：The effects of slope plate length on semi-solid microstructure of hypereutectic high Cr cast iron slurry have been observed.It is revealed that the length of slope plate has an obvious effect on the primary carbide in the cast iron.The nucleation and directional growth are dominant in primary carbide with the slope plate length less than 300 mm,while the primary carbide is spheroidized as a result of the collision and sharp corner melting with the slope plate length in range of 300 to 900 mm,in which the fine and round carbide with dispersive distribution can be obtained with the slope plate length of about 900 mm.Furthermore,the primary carbide can be merged and conglutinated each other with the slope plate length more than 900 mm.关键词：Hypereutectic High Cr Cast Iron;Slope Cooling Plate;Slope Plate Length;Primary Carbide
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- 176
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发布时间：2023-12-18 - 摘要：The microstructure of semi-solid Mg-10Al-4Zn alloy was observed by OM（optical microscope）,SEM（scanning electron microscope）,EDS（energy dispersive spectrometer） and LEXT.OM observation reveals that there exists the fine and round semi-solid microstructure with uniform distribution and higher solid fraction.The finer structure can be observed by SEM,and the melting firstly occurred in the boundary with higher solute concentration by combining with EDS analysis.LEXT observation indicates that the solid phase particle is spheroid in three-dimensional structure,which is composed of eutectic phase and remelting α-Mg phase by two-dimensional planar height diagram verification.关键词：Microstructural Analysis;Semi-solid;Mg-10Al-4Zn Alloy;Microstrucutral Observation
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- 195
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发布时间：2023-12-18 - 摘要：A series of true stress via true strain curves were mapped under given temperatures,including 250,300,350,400,450,500 ℃,and strain rate,including 0.1,0.01.0.001 s-1,based on the measurements of mechanical properties of squeezing casting aluminum alloy with different pressures,such as 20,50,75 MPa by means of digital-controlled thermal-mechanical physical analogue machine Gleeble-1500D.The effects of temperature,strain rate and squeezing pressure on the mechanical properties of the aluminum alloy at elevated temperature have been examined.The results indicate that the flow stress of the aluminum alloy is decreased with the increase of the temperature and is increased with the increase of the strain rate.The higher flow stress can be obtained with a higher squeezing pressure,exhibiting the effects of squeezing pressure on the mechanical properties of the aluminum alloy at elevated temperature.关键词：Squeezing Casting;Aluminum Alloy;Mechanical Properties at Elevated Temperature;Isothermal Compression
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- 429
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发布时间：2023-12-18 - 摘要：The improvement of gating system was conducted by analyzing the structure,dimension and processing features of airless gun,in which the one ingate was modified two ones that locates the higher position of components,and the declined core-drawing mechanism was cancelled to simplify the die structure.The qualified products were manufactured successfully with the improved mould by rational die casting process.关键词：Airless Gun;Die Casting Die;Gating System
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- 53
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发布时间：2023-12-18 - 摘要：Some countermeasures of preventing the deformation of castings in investment casting were expounded.Aiming at easily-deformed castings,the effective measures should be adopted from the first procedure,wax injection,to render the wax pattern in a desirable quality condition.The practical production verified that these countermeasures are effective and necessary for preventing the deformation of investment casting.关键词：Investment Casting;Wax Pattern;Measures
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- 542
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发布时间：2023-12-18 - 摘要：The deposition-deoxidization behavior of de-oxidizer in middle frequency furnace was expounded.It was found that the deoxidization ability is deteriorated with the increase of oxidization degree of the element when some elements reach to a certain in the furnace.The excessive addition of metal oxide element can improve deoxidization ability and reduce the oxygen content in molten steel to decrease non-metal inclusions,which is helpful for the purification of molten steel.关键词：Deposition-deoxidization;Oxidization Degree;Deoxidization Energy;Carbon-oxygen Balance
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- 160
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发布时间：2023-12-18 - 摘要：Effects of trace Sr on microstructure and mechanical properties of（Al2O3+Al3Zr）p/A356 composites synthesized by the direct melt reaction in A356-Zr（CO3）2 system were investigated by X-ray diffraction（XRD）,scanning electron microscope（SEM） and tensile test.SEM observation reveals that in-situ synthesized fine Al3Zr and Al2O3 particles with 23 μm in size can be observed,which is uniformly distributed into the matrix due to not be rejected by solid/liquid interface but be engulfed in the solid phase,and the Si phase in the A356 alloy can be converted from coarse acicular into fine particle with trace Sr modification.The tensile strength of the Sr modified composites is increased by 13.8% compared with that of the composites without Sr modification.关键词：Aluminum Matrix Composites;Microstructure;Mechanical Properties;Sr Modification
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- 140
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发布时间：2023-12-18 - 摘要：Ni-CeO2nano-composites were prepared by electroforming in an ultrasonic field.The effects of ultrasonic power,CeO2nano-particle addition and cathode current density on the content of CeO2 in the nano-composites have been investigated,and the electroforming velocity and current efficiency with the ultrasonic effect have been analyzed.The surface morphology and micro-hardness of the nano-composites have been examined.The results indicate that the desirable Ni-CeO2 nano-composites containing 3.0%CeO2 can be prepared with the CeO2 particles addition of 40 g/L and ultrasonic power of 300 W at frequency of 28 kHz and cathode current density of 6 A/dm2,exihiting more smooth morphology with more compact structure and finer grain size,compared with that of Ni-CeO2 nano-composites prepared in the absence of ultrasonic field.The ultrasonic field can promote the co-deposition of nano-particle with the matrix to further refine the grain size as a result of restraining the agglomeration of the nano-particle,and it can obviously increase the micro-hardness of the composites as well as raising the electro-forming speed and electric current efficiency.关键词：Ultrasonic Field;Electro-forming;CeO2 Particle;Nano-composites
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- 185
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发布时间：2023-12-18 - 摘要：The microstructure and properties of in-situ Ti2AlC/TiAl composites synthesized by vacuum pressure sintering in Al-Ti-C system were investigated by XRD（X-ray diffractometer）,SEM（scanning electron microscope）,OM（optical microscope） and tensile test,and the reinforced mechanism of Ti2AlC in TiAl alloy was approached.The results indicate that the composites are composed of Ti2AlC reinforcement,a few amounts of Ti3AlC phase and TiAl matrix.The creation of lamellar Ti2AlC reinforcement can refine the matrix grain size and restrain the propagation of crack,greatly improving the mechanical properties of the composites.The bending strength and fracture toughness of the composites reach 743.84 MPa and 9.17 MPa·m1/2,respectively.关键词：Ti2AlC/TiAl Composites;In-situ Synthesization;Mechanical Properties;Reinforced Mechanism
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- 264
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- 1
发布时间：2023-12-18 -
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- 摘要：The effects of surplus Si on microstructure and properties of 6063 aluminum alloy were approached,and the mechanism of the surplus Si was analyzed theoretically.It was found that the proper surplus-Si can refine as-cast microstructure and improve the mechanical properties of the 6063 aluminum alloy.The effects of surplus Si content with less than 0.06% on the corrosion resistance of the alloy can be neglected,however,excessive surplus Si content can significantly deteriorate the corrosion resistance.The electric conductivity of the alloy can be declined with the increase of surplus Si content,and the higher electric conductivity can be observed with the mass ratio of Mg via Si somewhat less than 1.73.关键词：6063 Aluminum Alloy;Surplus Si;Microstructure;Properties
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- 419
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发布时间：2023-12-18 - 摘要：The as-cast microstructures of Mg-5Sn-xGd（x=0,0.5,1.0,4.0,6.0） alloys have been observed.The experimental results indicate that with increasing in Gd content,the lamellar α-Mg+Mg2Sn eutectic phase which is mainly distributed continuously in the grain boundary areas of the alloy is reduced and becomes discontinuous.With 4% Gd addition,the eutectic phase in the alloy can be hardly found.In addition,a new fine Mg-Sn-Gd phase with irregular shape is generated in near grain boundary of the alloy with the decrease of eutectic phase,increased with increasing in Gd content.The DSC analysis indicate that the rare-earth phase has a phase transition at 582 ℃.The addition of Gd has an obvious effect on the distribution of the element Sn in the alloy.关键词：Mg-Sn-Gd Alloy;As-cast Microstructure;Rare Earth Phase
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- 222
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发布时间：2023-12-18 - 摘要：The effects of minor boron on microstructure of hypoeutectic Ti-5Si alloy have been observed by SEM（scanning electron microscope） and OM（optical microscope）,and the Boron atom role on the eutectic transformation and the growth of dendrite during solidification process has been investigated.The results show that the minor B addition can remarkably improve the morphology of the dendrite in the microstructure of hypoeutectic Ti-5Si alloy,decreasing the volumetric fraction of primary dendrite and increasing the volumetric fraction of eutectic phase,which is attributed to the minor B addition raising the Si equivalent value in the hypoeutectic Ti-5Si alloy.关键词：Ti-5Si Alloy;Hypoeutectic;Boron;Microstructure
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- 115
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- 1
发布时间：2023-12-18 - 摘要：The microstructure of laser cladding Al-Si alloy coating on the magnesium alloy surface was observed by SEM（scanning electron microscope） and EDS（energy dispersive spectrometer）.The results reveal that the cladding coating is composed of Mg17Al12,α-Mg phase and Mg17Al12 eutectic phase,α-Mg solid solution phase and Mg2Si phase.The absence of defects,such as gas hole or crack,can be observed due to the desirable bonding between cladding coating and the matrix.The coarse Mg2Si phase in the laser heat treatment cladding coating is transformed into fine particle and uniformly distributed into the grain boundary,improving the performance of the cladding layer.关键词：Laser Cladding;Microstructure;Magnesium Alloy
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- 147
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- 1
发布时间：2023-12-18 - 摘要：The effects of specimen size on cast γ-TiAl alloy have been observed.The results indicate that the average columnar crystal size is 320,436,543 μm with γ-TiAl alloy plate of 3,4,5 mm in thickness,respectively,showing a linear functional relationship.The average lamellar spacing is 1 353,1 494,1 540 nm,respectively,increasing with the increase of the thickness of the plate.In addition,the micro-hardness of the alloy is decreased with the increase of thickness of the alloy specimen.The variation of thickness of specimen changing the temperature gradient during solidification process is responsible for the change of microstructure and micro-hardness of the γ-TiAl alloy.关键词：Cast γ-TiAl Alloy;Size Effects;Columnar Crystal Size;Lamellar Spacing
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- 300
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- 1
发布时间：2023-12-18 - 摘要：The liquid-liquid structure transition of the Sn-70Bi alloy at more than liquidus in range of hundreds temperature has been investigated by direct current four-probe method.The reversibility of liquid-liquid structure transition and its influence on the solidification of Sn-70Bi alloy have been analyzed based on above mentioned result.It was found that the liquid-liquid structure transition of Sn-70Bi alloy exhibits partial reversibility,which is mainly related to the Sn molten structure,and the structure transition has obviously affect the solidification behavior and microstructure of the Sn-70Bi alloy.The under-cooling degree of the liquid-liquid structure transition melt can be greatly increased,which obviously refine the primary phase and eutectic phase.关键词：Liquid-liquid Structure Transition;Under-cooling Degree;Solidification Behavior;Sn-70Bi Alloy
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- 145
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发布时间：2023-12-18 -
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