等通道变形高纯铝的显微组织与力学性能

Microstructure and Mechanical Properties of High Purity Aluminum Processed by Equal Channel Angular Pressing

摘要: 采用光学显微镜和透射电镜研究了室温下高纯铝(纯度99.999 5%)经不同道次等通道变形后的显微组织,并对其进行了拉伸性能测试.结果表明:等通道变形可使高纯铝的晶粒显著细化,并出现了动态回复和动态再结晶;2道次等通道变形后,高纯铝的屈服强度和抗拉强度达到最大,分别为25.68 MPa和61.61 MPa,随后出现了应变软化并最终趋向一个定值;1道次后伸长率最小(35.88%),而后逐渐增大,12道次后又接近于退火态的伸长率(63.80%);应变软化现象与高纯铝在等通道变形中发生动态回复和动态再结晶有关.

Abstract: The microstructure and mechanical properties of high purity aluminum processed by equal channel angular pressing (ECAP) after 1,2,4,8,12 and 16 passes were investigated by optical microscope (OM),transmission electron microscope (TEM) and tensile tests at room temperature.It is shown that grains could be remarkably refined with the occurrence of dynamic recovery and dynamic recrystallization during ECAP.The strength reached a maximum value after 2 passes,and then decreased with the passes,and finally approached to a saturated value.The elongation had a minimum value of 35.88% after 1 pass,then it increased with the passes and reached the similar value of annealing state after 12 passes.The strain softening was contributed to the dynamic recovery and dynamic recrystallization during ECAP process.