深冷轧制对AISI 310S不锈钢组织和性能的影响

Effect of cryorolling on microstructure and mechanical properties of AISI 310S stainless steel

采用深冷轧制技术对AISI 310S奥氏体不锈钢进行不同变形量的实验,借助OM、SEM、TEM、XRD及微拉伸试验等方法研究了不同变形量下奥氏体不锈钢的组织特性及性能变化规律。结果表明:奥氏体不锈钢在深冷轧制不同变形量下均未发生应变诱发马氏体相变,在变形量为30%时,组织内部出现高密度位错且夹杂少量的形变孪晶,随着变形量增大至70%时,组织内部出现大量形变孪晶,孪晶与位错的交互作用显著加剧;到变形量为90%时,晶粒完全碎化至纳米量级。而且随着变形量的增大,强度指标大幅度上升,屈服强度、抗拉强度分别从原始态的305 MPa、645 MPa增加至1099 MPa、1560 MPa;而伸长率则从40.8%(原始)下降至6.4%(变形量90%),拉伸断口由韧性断裂向准解理断裂转变。

Microstructure and mechanical properties of AISI 310 S steel after cryorolling with different reductions were investigated by means of XRD,SEM,TEM and micro-tensile tests. The results show that the deformation-induced martensite transformation is not found during cryorolling. After 30% deformation,high density dislocations and a small amount of deformation twins are observed. With the increasing of deformation to 70%,a large amount of deformation twins form and the interaction between twins and dislocations is enhanced significantly. After 90% deformation,the grains are refined to nanometer level. With increasing of the deformation,the yield strength and tensile strength of the steel are improved from 305 MPa and 645 MPa( before cryorolling) to 1099 MPa and 1560 MPa( 90%deformation),respectively,but the corresponding elongation is reduced from 40. 8% to 6. 4%. The tensile fracture is changed from typical ductile fracture to brittle cleavage fracture.