BP-ECAP中背压和温度对铜变形的影响

Influence of backpressure and temperature on copper deformation in BP-ECAP

背压等通道转角挤压能够大大提高晶粒的细化度,同时防止裂纹的产生,使试样的微观组织和力学性能得到显著的提升。利用有限元软件Deform-3D,对已预压缩的铜切屑背压等径角挤压进行模拟,分析不同背压和温度条件下等效应变的变化,探索最佳温度和背压,使具有超细晶结构的铜切屑在块体成形的过程中,最大程度地提高致密性并保持其超细晶微结构。结果表明:当背压在0~50 MPa内、温度在20~300℃时,增大背压或温度,铜所受的等效应变增大,变形更为均匀,同时试样的致密度高;当背压超过50 MPa或温度高于300℃时,铜所受的等效应变会大幅度降低;当背压为50 MPa、温度为300℃时,铜所受等效应变最大、变形均匀、晶粒细化程度较好且致密度高。

Backpressure-equal-channel angular pressing(BP-ECAP)can greatly improve the grain refinement and prevent the generation of cracks at the same time,so that the microstructure and mechanical properties of sample are significantly improved.Then,the backpressure-equal-channel angular pressing process of pre-compressed copper chips was simulated by finite element software Deform-3 D,and the changes of equivalent strain under different backpressures and temperatures were analyzed to explore the optimal temperature and backpressure,so that the copper chips with ultra-fine crystal structure improved the compactness and maintained its ultra-fine crystal microstructure to the maximum extent during the block forming process.The results show that when the backpressure is within 0-50 MPa or the temperature is between 20-300℃,increasing the backpressure or temperature increases the equivalent strain on the copper,the deformation is more uniform,and the compactness of sample is high.However,when the backpressure exceeds 50 MPa or the temperature is higher than 300℃,the equivalent strain on the copper is greatly reduced.Finally,when the backpressure is 50 MPa and the temperature is 300℃,the copper is subjected to the largest strain,the uniform deformation,the better grain refinement and the high compactness.