ECAP过程中TWIP钢的组织演变

Microstructure Evolution of TWIP Steel During Equal Channel Angular Pressing

研究了TWIP钢（30Mn-3Si-3A1）在等径角挤压冷变形过程中的组织演变。结果表明，1道次变形后，产生大量10-40nm宽的形变孪晶，同时出现的微观剪切带对孪晶进行了切割。随着道次的增加，孪生系统增多，形变孪晶相互交割。同时剪切带的数量增加，产生相互交错并切割孪晶板条。4道次变形后，组织变成由碎化带和割裂开的孪晶相互交织的变形结构。碎化部分超细晶晶粒尺寸为40～120nm，而未碎化孪晶板条宽度降至5～20nm。

The microstructure evolution of a TWIP steel during equal channel angular pressing （ECAP） was investigated experimentally. After one pass, a large number of deformation twins with band widths of 10--40 nm were produced. At the same time, these deformation twins were cut down by microshear bands. With increase of pressing passes, more twinning systems were activated and twin bands intersected each other. Also shear bands cut twinning bands and refine more area of microstructure. After 4 pressing passes, ultrafine grains with size of 40--120 nm were obtained. While several areas within which deformation twins were not cut down were distributed in the matrix of ultrafine grains. The width of these twin bands was decreased to 5--20 nm.