最新刊期
卷 ， 期 11 ， 2008
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- 摘要：Effects of SiC particle on grain refinement of AZ91D alloy were investigated by adding SiC particle directly into AZ91D alloy melt,and the refining mechanism was approached.It is concluded that SiC particle plays three roles in refining grain size in AZ91D alloy melt.Firstly,part SiC particle is taken as heterogeneous nuclei for primary Mg.Secondly,some restrain the growth of grain size as a result of exerting interface of liquid/solid during solidification.Thirdly,creation of rod-like Al4C3 phase is observed due to the release of C atom into the melt.The grain size can be remarkably refined due to the interaction of the three effects.关键词：SiC;AZ91D Magnesium Alloy;Grain Refinement;Heterogeneous Nucleation
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发布时间：2023-12-18 - 摘要：The flow stress behavior of Al-Cu-Mg-Ag alloy was tested with Gleeble-1500 machine by isothermal compression at 300～500℃ and strain rate at 0.01～10 s-1,and a constitutive equation model for hot deformation of the alloy was established.The results reveal that the flow stress is increased with decreasing in temperature and increasing in strain rate.The flow stress of the alloy is sharply increased to peak value and then tends towards a constant with raising in strain rate in case of strain rate less than 10 s-1,showing dynamic recovery,while it reaches the peak value and then decreases with the occurrence of saw-tooth fluctuation in case of strain rate of 10s-1 and deformation temperature more than 300 ℃,exhibiting partial dynamic recrystallization.The flow stress of Al-Cu-Mg-Ag alloy during high temperature deformation can be expressed by the Zener-Hollomon parameters in the hyperbolic sine function,and deformed activation energy of the alloy makes 160.08 kJ/mol.关键词：Al-Cu-Mg-Ag Alloy;Hot Deformation;Flow Stress;Constitutive Equation
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发布时间：2023-12-18 - 摘要：Effects of modification on as-cast microstructure and mechanical properties of lead brass in permanent mold were investigated,and the solidification mode and solidification structure transformation of slush cup were observed by pouring testing.The results reveal that solidification structure of un-modified slush cup with coarse inner face consists of coarse α and β dendrite,and solidification mode is evolved from sequential solidification into mixing solidification of sequential solidification with mushy solidification,while that of modified one in which the inner face is transformed from coarse into smooth is composed of fine equiaxed grain in surface and narrow dendrite zone as well as equiaxed grain in inner.Microstructural observation shows that the microstructure is converted from dendrite into fine equiaxed grain.关键词：Modification;Lead Brass;Slush Cup;Microstructure;Mechanical Properties
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发布时间：2023-12-18 - 摘要：Effects of Bi on microstructure and properties of Al-Si piston alloy were observed by SEM（scanning electronic microscope）,OM（optical microscope） and tensile testing.The results show that Bi element can form monotectic transition with Al,and it exists as dispersive Bi phase independently in the microstructure of Al-Si piston alloy.The dimensional stability and wear resistance of the Al-Si piston alloy are greatly improved due to the special physical property and self-lubricity of Bi particle.The dimensional change rate of eutectic Al-Si piston alloy is decreased by 26.3% and of hypereutectic Al-Si piston is decreased by 7.7%～9.0%.In addition,the wear resistance of hypereutectic Al-Si piston alloy with Bi is decreased by approximately 50%.
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发布时间：2023-12-18 - 摘要：Effects of gas flow,rotor speed,refining time and holding time in rotary impeller refinement method on purification of 7075 aluminum alloy were examined by orthogonal design.Meanwhile,effects of C2Cl6 refinement,rotary impeller degassing refinement and combined method of the two technologies on degassing in aluminum alloy were comparatively approached.The results show that rotor speed is the most dominant factor affecting on degassing,and then gas flow,refinement time,then holding time.The desirable purification of 7075 aluminum alloy can be observed with rotor speed at 400 r/min and gas flow of 0.4 mL/h,refinement for 15 min as well as holding for 6 min.Hydrogen-degassing rate in C2Cl6 refinement method is approximately 34.5% while it is approximately 70% in rotary impeller degassing method.Alternatively,the hydrogen-degassing rate in combined method of C2Cl6 refinement method with rotary impeller degassing method can reach up to 78%,exhibiting acceptable purification effects.The tensile strength,yield strength and elongation of 7075 aluminum alloy refined by combined method of C2Cl6 refinement with rotary impeller degassing method are superior to those of one refined by rotary impeller degassing method which is superior to those of one refined by C2Cl6 refinement method.关键词：Aluminum Alloy;Rotary Impeller Degassing Method;Refinement;Combination Refinement
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发布时间：2023-12-18 - 摘要：Ni60 coating was prepared from the self-fusing alloy powder by induction cladding in refractory coating protection.Microstructure of the Ni60 coating was observed by optical microscope（OM）,SEM（scanning electronic microscope）,EPMA（electronic micro-analysis） and XRD（X-ray diffraction）,and hardness of the coating was measured also.The results reveal that the coating exhibits desirable metallurgical bonding mechanism with the matrix alloy,in which compact microstructure with little non-metallic inclusion and low porosity rate as well as uniformly distributed hardness can be presented.The cladding thickness can reach up to 0.6mm in one induction cladding,which is far superior to that of one prepared by the other cladding methods.Meanwhile,the coating quality is equivalent to that in vacuum cladding as a result of overcoming the shortcoming of induction cladding without protective coating.
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发布时间：2023-12-18 - 摘要：Important role of melt-treatment for liquid Al and theory on high efficient melt-treatment as well as key techniques were expounded.Furthermore,effects of melt-treatment techniques such as high efficient purification,modification of impurity-phase containing Fe-rich and grain refinement on the Al melt quality and interrelation among these treatment techniques were approached.The principle of melt-treatment that purification is a key process of Al melt treatment and base of refinement and modification is presented.Based on the principle,high efficient melt-treatment techniques were developed to be applied to the preparation of Al sheets for the can with high performance,which can significantly improve the mechanical properties of the Al sheets,especially the ductility,due to the great improvement of melting quality of the Al sheets,helpful for the sequent rolling and performance of the finished product.关键词：Al Sheets with High Performance;Molten Al;Purification;Modification;Grain Refinement;Melt-treatment Techniques
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发布时间：2023-12-18 - 摘要：A special copper alloy CAD system,which is developed on the basis of the national standards,can availably improve the efficiency and accuracy of casting process design.Key unites in CAD system for copper alloy casting are described including initializing drawing setting,real-time graphics rendering,menu development and exchanging data between Access and ODBC based on the MFC,and its application is introduced also.关键词：Key Unites;Copper Alloy CAD System;Casting Process;AutoCAD Software
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发布时间：2023-12-18 - 摘要：Filling process of magnesium alloy air-intake manifold in permanent tilted casting was simulated by the Anycasting software.The optimized processing parameters were obtained by orthogonal testing and numerical simulation.The orthogonal testing reveals that the factors influencing filling process are as follows:pre-heated temperature of mould,then tilted velocity,pouring temperature and then preheated temperature of cup.
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发布时间：2023-12-18 - 摘要：The semi-solid slurry with fine near-spheroidal structure of AZ91D alloy was prepared bya rotary pouring method.The results reveal that the primary phase particles with distributed fine spheroidal in semi-solid structure can be presented with decreasing the pouring temperature and increasing rotating velocity of the duct as well as choosing proper declined angular.The desirable semi-solid microstructure can be obtained with pouring at 630 ℃ and rotating at 75 r/min as well as declined angle of 25°.关键词：Rotating Duct;Slurry Preparation;Pouring Temperature;Microstructure
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发布时间：2023-12-18 - 摘要：Semi-solid billets of hypoeutectic high Cr cast iron prepared by the sloping plate method were reheated at 1300℃,and the evolution of pro-eutectic austenite in the semi-solid billets during reheating was observed by the Leica image analyzer.It is found that the spheroidization and the exacerbation due to mergence growth as two main forms for the evolution of austenite during holding have been generated by turns.With increasing in holding time,the spheroidization and the mergence growth time are increased,and the exacerbation due to mergence growth becomes more prominent also.The grain with shape factor of 0.86 and average equivalent diameter of 78.8 μm can be obtained with holding for 15 min,while the grain with shape factor of 0.7 and average equivalent diameter of 104.1 μm can be obtained with holding for 60 min.关键词：Sloping Plate Method;Semi-solid;Hypoeutectic High Cr Cast Iron;Pro-eutectic Austenite
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发布时间：2023-12-18 - 摘要：Effects of Y and Ce addition on microstructure and mechanical properties of squeezing casting Mg-6Al alloy were investigated by OM（optical microscope） and SEM（scanning electron microscope）,universal tensile tester.The results indicate that microstructure of squeezing casting Mg-6Al alloy is transformed from net-like structure into discontinuous net-like structure,in which the grain size is greatly refined,and mechanical properties of the alloy at room temperature can be significantly raised with Y and Ce mixed addition.Tensile strength and elongation of the squeezing casting Mg-6Al alloy with 0.5% Ce and 0.5% Y addition are increased from 126 MPa to 200 MPa and from 1% to 8.5%,respectively.关键词：Mg Alloy;RE;Squeezing Casting;Microstructure;Mechanical Properties
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发布时间：2023-12-18 - 摘要：The structure characteristics and operation mechanism of the die casting die with demountable sliding block and bending tie bars driven by the hydro equipment were introduced.Bending tie bars drew-pulled the sliding block by hydraulic core-pulling devices and mould opening forces to loose the demountable sliding block.In addition,the side-pulling core for the die castings is controlled by sliding block mechanism with oblique pin,and stream distribution cone also can be run as an insert in the die.The die exhibits reliability and convenience in operation and improves the accuracy of produced parts due to solving the problem in drawing the demountable sliding blocks.关键词：Bending Tie Bar;Demountable Sliding Block;Stream Distribution Cone;Insert;Die Casting Die
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发布时间：2023-12-18 - 摘要：We have developed some key unites related to high vacuum die casting process based on MFT（minimum filling time） method,including shut-off valve,vacuum system,sealing structure of die,releasing agent and gating system.The mechanical properties and microstructure of ZL101 alloy in high vacuum die casting process were researched.The results indicate that,compared with those of one in conventional die casting,tensile strength and elongation of the ZL101 alloy in high vacuum die casting reach up to 204.55 MPa and to 8.41%,increased by 17.16% and by 71.98%,respectively,showing the great improvement of mechanical properties,especially ductility.However,compared with as-cast one,T6 treated ZL101 alloy after high vacuum die casting are increased by 7.68% in tensile strength and decreased by 6.78% in elongation.关键词：High Vacuum Die Casting;Al-Si-Mg Alloy;Strength;Ductility;Microstructure
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发布时间：2023-12-18 - 摘要：Production of the high quality investment castings is dependent on rational gating system design and proper castings structure.Modified equation for gating system was derived by altering parameters in empiric formula for gating system design and determining the applied scope and boundary conditions on the basis of analysis of data from conventional gating system design for investment castings with computer by mathematical statistics method,which can guide other gating system design with the similar working conditions.In addition,the quality of investment castings can be greatly improved by pertinentl application or combination application of above two ways based on castings structure,remarkably reducing shrinkage porosity（hole） and rising product rate and production yield rate.
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发布时间：2023-12-18 - 摘要：It is difficult to design and machine the investment casting mould for the forth-level large turbine blade of a heavy gas-turbine due to its complicated structure and large dimension as well as high accuracy requirement.Design and machining of the mould were described,in which the loop dimension is ensured by adopting segmentation treatment for blade body,and fabrication hole is used to localize the mould machining during installation manufacturing,and self-locking clamping unites are adopted to ensure the stability of working time of the mould.关键词：Large Blade;Investment Casting;Design of Mould Parting;Fabrication Hole;Self-locking Clamping Mechanism
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发布时间：2023-12-18 - 摘要：EVA plastic film is the key material for vacuum molding process.The special EVA film with elongation of 800% in longitudinal direction and 700% in horizontal direction and the minimum thickness of 0.08 mm for V-process are developed,which can meet different requirements from the enterprises and can be used for large cast steel parts,such as manganese steel railway frog,steel castings of rocking support,side frame for train and the steel bridge box for engine truck.关键词：Vacuum Molding Process;EVA Plastic Film;Steel Components
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发布时间：2023-12-18 - 摘要：A mathematical model was used to investigate the liquid steel flow characteristics in centrifugal flow tundish for continuous casting.Effects of dam position and rotating magnetic intensity on flow structure were described,and the availability of calculation results was verified by the experiment.The results indicate that a near-distance from the dam to the exit of rotation chamber can promote the formation of the circumfluence in the distribution chamber,which is beneficial for removing inclusion,while a larger distance can result in obvious asymmetry flow structure in distribution chamber,and the asymmetry structure is more and more evident with the increase of dam distance,which is unfavorable for the mixture of liquid steel,leading to the formation of blind zone.Effects of magnetic flux intensity on liquid steel flow pattern can be neglected with the magnetic intensity more than a critical value.关键词：Centrifugal Flow Tundish;Flow Characteristics;Numerical Simulation;Asymmetry
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发布时间：2023-12-18 - 摘要：The equation describing the meniscus shape in two-section slitless mold for soft-contact electromagnetic continuous casting was derived from theoretical analysis.The equation modified by the experimental results can be used to calculate accurately the meniscus shape,and prediction of meniscus shape of liquid steel in mold with 178 mm in diameter by the equation reveal that the height of meniscus is increased with increasing in the power and resistivity of top half of the mold,and it is decreased with increasing in frequency and thickness of the mold.The soft-contact electromagnetic continuous casting can be realized by using rational structural and electromagnetic parameters.关键词：EPM（Electromagnetic Processing of Materials）;Soft-contact Electromagnetic Continuous Casting;Two-section Slitless Mold;Electromagnetic Field;Meniscus
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发布时间：2023-12-18 - 摘要：Cu cladding Al contact wire with 160mm2 in cross section and（1.0±0.1） kg/m in linear density was fabricated by the drawing compound method,and properties of the wire were examined.It is found that the comprehensive electronic conductivity,bonding force and fracture force of the Cu cladding Al contact wire make 45.82 MS/m,60N/m and 47kN,respectively,which can be used for magnetic floating power track with loads of 2000A.关键词：Drawing Compound Method;Cu Cladding Al;Contact Wire
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发布时间：2023-12-18 - 摘要：Magnesium alloy matrix composites（MMCs） were fabricated by squeezing-infiltration casting with the perform made of crystallined aluminum silicate short fibers as reinforcement and aluminum phosphate as binder at high temperatures.Drying sliding friction and wear resistance of the MMCs were examined by means of MM200 wear tester（block-on-ring configuration） against a hardened alloy steel counterface with 53HRC under loads of 10,30 and 50N at 0.47 m/s and 0.92 m/s,and the wear morphology of the tested specimens was observed by SEM（scanning electronic microscope）.The results indicate that wear mechanism of the MMCs is characterized by abrasive wear with loading 10 N and 30 N at 0.47m/s,while it is characterized by abrasive wear with slight flaking wear with loading 50 N at 0.47m/s,and it exhibits combined wear of abrasive wear with slight adhesive wear with loading 50 N at 0.94 m/s,increasing the wear resistance of the MMCs.关键词：Aluminum Silicate Fiber;AZ91D Alloy;Magnesium Matrix Composites;Wear Mechanism
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发布时间：2023-12-18 - 摘要：Mg-Al-C master alloy for grain refinement of Mg-Al series alloy was fabricated by a special powder metallurgy method,in which Al（C） solid solution is distributed at the boundary of magnesium particles.The results show that the master alloy exhibits satisfactory refining effects on AZ31 magnesium alloy.The grain size of AZ31 alloy is decreased from 850μm to 260 μm with 3% Mg-Al-C master alloy content.Refining mechanism of the master alloy on AZ31 alloy is approached.关键词：AZ31 Magnesium Alloy;Grain Refinement;Mg-Al-C Master Alloy
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发布时间：2023-12-18 - 摘要：Effects of Zn and Gd on the as-cast microstructure and mechanical properties of Mg-Zn-Gd alloys were investigated by menas of optical microscope（OM）,XRD（X-ray diffraction）,SEM（scanning electron microscope） and tensile testing at room temperature.The results reveal that Gd content plays an important role in the phase constitution of the alloys.When given a fixed Zn content,with the increase of Gd content,the second phase transformation was observed as follows:Mg7Zn3 phase +Iconsahedral quasicrystalline phase（I phase）→I phase →I phase +W phase.Meanwhile,the secondary dendrite arm is evidently decreased and morphology of the interdendrite is evolved from particle into needle-like structure and then into closed net-like structure.When the atomic ratio of Zn to Gd keeps constant of 5.8,with increasing in total content of Zn and Gd contents,the second phase constituent sustains stable,however,the more fine dendrite phase is distributed into the microstructure with the increase of second phase volume fraction.Tensile testing indicates that when the Zn is given a fixed value,with increasing in Gd content,both the tensile strength and elongation of the alloy are improved,however,the yield strength is firstly increased and then decreased.In addition,when the atomic ratio of Zn to Gd keeps a constant value of 5.8,with increase of the total content Zn and Gd,the alloy exhibits higher strength and lower elongation.
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发布时间：2023-12-18 - 摘要：The surface morphology and corrosion resistance of the stannate conversion coating on AZ91D magnesium alloy at different grow stages were investigated by SEM（scanning electron microscope）,EDS（energy diffraction spectrum） and XRD（X-ray diffraction） as well as salt immersion testing.The results show that in the initial stage of chemical treatment,the MgSnO3 coating is deposited on the α phase very fast,resulting in the rapid increase of coating weight.After 10 min,the stannate conversion coating is deposited on the β phase with the decrease of growth rate.Then,the dissolution of conversion coating is accelerated on the α phase as a result of its loose structure,meanwhile,new coating is continuously deposited on the α phase,resulting in the dynamic balance.With increasing in chemical treatment time,the dissolution rate of coating is higher than deposition rate,which leads to the decrease of coating weight.The stannate conversion coating exhibits desirable corrosion resistance after chemical treatment for about 30 min.关键词：Magnesium Alloy;Stannate Conversion Coating;Growth Mechanism
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发布时间：2023-12-18 - 摘要：The microstructure of beta Ti alloy Ti-11Mo-6Zr-4Sn（TMA） in which some Mo and Sn are substituted by Cr,Fe and Ce was observed by XRD（X-ray diffraction）,SEM（scanning electron microscope） and EDS（energy dispersive spectrumeter）,and the elastic modulus as well as microhardness was measured by CSEM nano-indentation and micro-sclerometer.Furthermore,effects of alloying elements and homogenization treatment on microstructure and mechanical properties of the TMA were described.The results indicate that β phase structure in TMA is independent of the Ce and Fe addition after and before homogenization treatment.Although the dominant phase in the TMA is not affected,precipitation of a little α phase and ω phase can be observed in the TMA alloy after homogenization treatment with Ce and Sn addition.The Young’s modulus and micro-hardness of the TMA alloy are increased with Cr and Fe substituting for Mo and Sn,while they are decreased with Ce substituting for Mo.关键词：Alloying Element;Beta Type Ti Alloy;Mechanical Properties;TMA
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发布时间：2023-12-18 -
Influence of Preparation Technology on High Temperature Oxidation Behavior of Cu-Si and Fe-Si Alloys
摘要：High temperature oxidation behaviors of Cu-1Si and Fe-1Si alloy prepared by CA（chemical alloying） and MA（mechanical alloying） were examined in pure O2 atmosphere at different temperatures.Analysis of high temperature oxidation kinetics of the alloys shows that MA is beneficial to improving the oxidation resistance of the Cu-1.3Si alloy,however,it is harmful to the oxidation resistance of Fe-1Si alloy.The structure of Fe-1Si alloy and Cu-1.3Si alloy prepared by MA and CA,respectively,was examined by XRD（X-ray diffraction）,SEM（scanning electronic microscope） and EDX.The oxidation film with Fe2O3→Fe3O4+FeO→FeO→FeO+SiO2 structure is formed in Fe-1Si alloy prepared by both MA and CA,and the oxidation film with CuO→Cu2O→Cu2O+SiO2→internal oxidization zone structure can be generated in Cu-1.3Si alloy.In addition,continuous SiO2 film is absent in mixed oxidation zone with SiO2 enrichment.Effects of grain size on high temperature oxidation behavior of two kinds of alloy prepared by both MA and CA method were described.关键词：MA;Grain Refinement;Cu-Si Alloy;Fe-Si Alloy;High Temperature Oxidation- 2
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发布时间：2023-12-18 - 摘要：Formation and growth of IMC in interface of Sn-2.5Ag-0.7Cu-0.1RE/Cu during aging were investigated by SEM（scanning electron microscope） and XRD（X-ray diffraction）.The results reveal that lamellar Cu3Sn phase near by Cu side in the solder joint can be created with aging at 85 ℃,125 ℃ and 150 ℃.With extending aging time,formed Cu6Sn5 phase in the solder joint is converted from wave-like structure into scallop-like one with bigger size and then into lamellar one.The growth thickness of Cu6Sn5 phase and Cu3Sn phase are linearly proportional to the square root of aging time,which is controlled by diffusion mechanism.The activation energies are 81.7kJ/mol and 92.3kJ/mol,respectively.关键词：Sn-2.5Ag-0.7Cu-0.1RE/Cu Interface;IMC;Aging;Activation Energy
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发布时间：2023-12-18 - 摘要：A new free-cutting brass bar with lead free and Sb and Mg was prepared by hot extrusion,which was further treated by quenching and aging.Microstructure of hot extruded and quenched and aged brass was observed by EPMA（electron probe microscopic analyzer） and EDS（energy dispersive spectrometer）,and cutting behavior of the hot extruded brass was examined by the tensile testing and lathe turning.The results indicate that the microstructure of the hot extruded brass containing Sb and Mg is composed of α phase,β phase and metallic compound with Sb and Mg,and it is equivalent to HPb59-1 brass in mechanical properties and is superior to the HPb59-1 brass in corrosion resistance as well as lower in wear resistance and close to brass with lead free from the German in cutting-free performance.The cutting-free behavior of the quenched brass with lead free can be obviously improved after aging treatment as a result of precipitation of uniformly distributed fine metallic compound with Sb and Mg.So,the cutting-free brass with lead free and Sb and Mg can replace HPb59-1 brass in production,realizing circumstance protection with the same economic cost.关键词：Brass with Lead Free;Brass containing Sb and Mg;Hot Extrusion;Microstructure;Mechanical Properties;Cutting-free Performance
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发布时间：2023-12-18 -
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