SiCp/6061Al合金复合材料的单轴循环变形行为及其时间相关特性

对T6热处理后的6061Al合金与SiCp／6061Al合金复合材料（14％，21％SiCp）的室温单轴循环变形行为进行了实验研觅讨论了基体合金和其复合材料在不同加载条件下的循环软／硬化行为和棘轮变形特征．实验研究表明：复合材料在宏观层次上体现出与基体相类似的应变循环特性和棘轮变形规律，即复合材料在非对称应力循环下也将产生一定的棘轮变形，并随应力幅值和平均应力的增加而增加；颗粒的引入使复合材料抵抗棘轮变形的能力增强，棘轮变形随颗粒含量升高而下降；复合材料的棘轮行为具有明显的时间相关特性，棘轮应变值依赖于应力率和峰值保持时间．研究得到了一些有助于复合材料循环变形行为本构描述的结论．

Uniaxial Cyclic Deformation of Sicp/6061Al Alloy Composites and Its Time--Dependence

The uniaxial cyclic deformations of T6-treated 6061A1 alloy and SiC_p/6061Al alloy composites(14%,21% SiC_p)were studied experimentally at room temperature.The cyclic soften- ing/hardening features and ratcheting behaviors of unreinforced matrix and the composites were dis- cussed under the different loading conditions.It is shown that the strain cyclic characteristics and ratcheting behavior of the composites are similar to those of the un-reinforced matrix in macro-scale, namely,the ratcheting also occurs in the composites under asymmetrical stress cycling and the ratch- eting strain increases as the stress amplitude and mean stress increased;however,the addition of SiC_p increases the resistance of the composites to ratcheting,and the ratcheting strain decreases as the volume fraction of SiC_p increased;the ratcheting has great time-dependence,i.e.,the ratcheting strain depends on the stressing rate and peak stress hold time.Some significant conclusions are obtained, which is useful to construct a constitutive model to describe the cyclic deformations of the composites.