中高体积分数SiC_p/Al复合材料的力学性能及强化机制  

Mechanical properties and strengthening mechanism of medium and high volume fraction SiCp/Al composites

作　　者：崔岩 廖家杰 曹雷刚 杨越 CUI Yan;LIAO Jiajie;CAO Leigang;YANG Yue(School of Mechanical and Materials Engineering,North China University of Technology,Beijing 100144,China)

机构地区：[1]北方工业大学机械与材料工程学院,北京100144

出　　处：《材料工程》2024年第4期110-119,共10页Journal of Materials Engineering

基　　金：国家重点研发计划项目(2017YFB0703102);北京市优秀人才培养资助个人项目(2016000020124G015)。

摘　　要：采用热等静压粉末冶金工艺,以2024和6061铝合金为基体,分别制备体积分数为35%,45%,55%的中高体积分数SiC_(p)/Al复合材料。探究基体合金与SiC体积分数对复合材料力学性能的影响。结果表明:相同体积分数时,以2024铝合金为基体的复合材料具有更高的弯曲强度和弹性模量;但以6061铝合金为基体的复合材料则呈现出了更高的断裂应变。随着体积分数的增加,两类复合材料力学性能的变化规律相同,弯曲强度呈先增大后减小的趋势,当体积分数为45%时达到峰值,分别为656.54 MPa和548.00 MPa;弹性模量呈持续上升趋势,当体积分数为55%时分别达到202 GPa和188 GPa。基体合金差异对力学性能的影响在体积分数较低时更为明显,提高体积分数将会弱化这种差异。结合理论公式计算发现,对于微米级的增强体颗粒,Orowan机制带来的强化效应极小,可忽略不计;其他各类强化机制的强化效果将随着增强体体积分数的增加呈现不同程度的提高;几何必须位错强化和热错配强化对材料屈服强度的贡献始终占据主导地位。The medium and high volume fraction SiC_(p)/Al composites were prepared by hot isostatic pressing powder metallurgy process with volume fractions of 35%,45%and 55%using 2024 and 6061 aluminum alloys as the matrix,respectively.The effect of matrix alloy and SiC volume fraction on the mechanical properties of the composites was investigated.The results show that with the same SiC volume fraction,composites with 2024 aluminum alloy matrix have higher bending strength and elastic modulus,while composites with 6061 aluminum alloy matrix present higher fracture strain.Meanwhile,the mechanical properties of composites with 2024 and 6061 alumium alloy matrix present the same trend as SiC volume fraction increases.The bending strength increases at first and then decreases,with the maximum values of composites with volume fraction of 45%being 656.54 MPa and 548.00 MPa,respectively.However,the elastic modulus continuous increases and reaches maximum for SiC_(p)/2024Al and SiC_(p)/6061Al composites with volume fraction of 55%being 202 GPa and 188 GPa,respectively.The effect of differences in matrix alloys on mechanical properties is more significant at lower volume fractions,and increasing the volume fraction will weaken this difference.According to the theoretical formulas calculation,Orowan mechanism has negligible strengthening effect for the composites with micron-grade SiC particle.The strengthening effect of other types of reinforcement mechanisms can be enhanced on different levels with the increase of the volume fraction of the reinforcement,wherein the contribution of geometrically necessary dislocations and thermal mismatch reinforcement to the yield strength of materials is always dominant.

关 键 词：SIC_P/AL复合材料 体积分数 力学性能 强化机制 

分 类 号：TB331[一般工业技术—材料科学与工程]