奥氏体不锈钢316L在ECAP过程中的组织演化及力学性能

对奥氏体不锈钢316L进行等效应变为1.02的6道次室温等通道挤压(ECAP)试验。结果表明,在ECAP挤压过程中316L发生了剪切滑移变形和孪生变形及晶粒碎化,经过4和6道次挤压后分别得到平均晶粒尺寸约80 nm和约61 nm的均匀分布的等轴晶粒。在1道次ECAP挤压后316L的抗拉强度由674 MPa增加到984 MPa, 规定塑性延伸强度则由594 MPa增加到922 MPa,维氏显微硬度由116.33 HV增加到328.31 HV,但是塑性下降严重,可以通过600 ℃后续退火处理进行改善。

Microstructure evolution and mechanical properties of austenitic stainless steel 316L during ECAP process

A 6-step room temperature equal channel extrusion( ECAP) test of equivalent strain to 1. 02 was carried out on 316 L austenitic stainless steel. The results show that the shear slip deformation,twinning deformation and grain fragmentation occur in the steel during ECAP extrusion,and equiaxed grains with average grain size of 80 nm and 61 nm are obtained respectively after 4 and 6 passes of extrusion. After 1 pass of ECAP extrusion,the tensile strength and the proof strength plastic extension of the steel increase from 674 MPa to 984 MPa and from 594 MPa to 922 MPa respectively,and the Vickers microhardness increases from 116. 33 HV to 328. 31 HV,but the plasticity decreases seriously,which can be improved by subsequent annealing at 600 ℃ .