微米/纳米复合结构奥氏体不锈钢形变机理及应变硬化行为  

Deformation mechanism and strain hardening behavior of micrometer / nanometer scale austenitic stainless steel

作　　者：万响亮[1] 李光强[1] 周博文[1] 马江华[1] 徐光[1] 

机构地区：[1]武汉科技大学钢铁冶金及资源利用省部共建教育部重点实验室,湖北武汉430081

出　　处：《材料热处理学报》2015年第11期72-78,共7页Transactions of Materials and Heat Treatment

基　　金：国家自然科学基金(51501134)

摘　　要：对Fe-17Cr-7Ni采用77%冷轧和700℃退火100 s工艺获得纳米晶（〈100 nm）/超细晶（100~500 nm）和部分粗晶（〉1μm）组成的微米/纳米复合结构奥氏体组织,其平均晶粒尺寸为500 nm。通过拉伸实验研究了微米/纳米复合结构奥氏体不锈钢力学性能、形变机制和应变硬化行为。结果表明这种微米/纳米复合结构奥氏体不锈钢屈服和抗拉强度分别为939 MPa和1098 MPa,伸长率高达38.8%。分析应变硬化率曲线表明拉伸过程中形变分为四个区间。结合透射电镜组织观察结果,发现形变过程中粗晶奥氏体先转化为形变马氏体,随后纳米晶/超细晶奥氏体转变为形变孪晶,表明这种高强度高塑性微米/纳米复合结构奥氏体不锈钢形变机制为TWIP和TRIP复合形变机制。Austenite microstructure with micron / nanometre size of Fe-17Cr-7Ni austenitic stainless steel after cold rolling to 77% reduction and annealing at 700℃ for 100 s was obtained,the auwtenite grains were consists of mainly nano（ 〈 100 nm） / ultrafine（ 100-500 nm）grains and a small amount of coarse（ 〈 1 μm） grains,and the mean size of grains was 500 nm. The mechanical property,deformation mechanism and strain hardening behavior of the steel were investigated by tensile testing. The results show that the yield strength,tensile strength and elongation of the steel are 939 MPa,1098 MPa and 38. 8%,respectively. The plastic deformation region was divided into four sub-regions based on the change in strain hardening rate. Combined with TEM analysis of tensile deformation samples,the straininduced martensite firstly occurrs in coarse grain and subsequently twinning is generated in the austenite with nanograined / ultrafine-grained structure. The deformation mechanism of this high strength-high ductility micrometer / nanometer scale austenitic stainless steel is the combination of twinning and strain-induced martensite.

关 键 词：奥氏体不锈钢 形变机制 应变硬化 奥氏体稳定性 

分 类 号：TG142.7[一般工业技术—材料科学与工程]