异构片层结构304不锈钢的制备及其力学性能

采用形变诱导马氏体退火逆转变工艺制备了异构片层结构(HLS)的304奥氏体不锈钢。通过扫描电镜和X射线衍射仪分析了304奥氏体不锈钢的显微组织和物相组成,并采用室温拉伸试验研究了其力学性能。结果表明,通过变形量为34%的热轧、75%的冷轧以及700 ℃退火12 min后,试验钢中的马氏体相逆转变为奥氏体相,部分残留奥氏体发生再结晶,获得了由微米再结晶晶粒与超细晶/纳米晶晶粒以及残留奥氏体晶粒组成的异构片层结构,微米再结晶晶粒和残留奥氏体被超细晶/纳米晶晶粒所包围。异构片层结构304奥氏体不锈钢的屈服强度为940.1 MPa,断裂总延伸率为43.1%,获得了良好的强度-塑性匹配。

Preparation and mechanical properties of 304 stainless steel with heterogeneous lamella structure

304 austenitic stainless steel with heterogeneous lamella structure(HLS) was fabricated by deformation induced martensite annealing reversion process. Microstructure was characterized by scanning electron microscope(SEM) and phase composition was analyzed by means of X-ray diffractometer(XRD). The mechanical properties of the 304 stainless steel with different grain sizes were studied systematically by means of quasi-static uniaxial tensile test at room temperature. The results show that after hot rolling with deformation of 34%, cold rolling with deformation of 75% and annealing at 700 ℃ for 12 min, the martensite in the tested steel reversely transforms to austenite, and part of the retained austenite is recrystallized. The original coarse grain structure is morphed into heterogeneous lamella structure, which is composed of nano/ultrafine grains, a proper amount of recrystallized grain clusters and retained austenite grains. Recrystallized grain clusters and retained austenite grains are sandwiched by nano/ultrafine grains. It is especially noted that a high yield strength of 940.1 MPa and a good percentage total extension at fracture of 43.1% can be simultaneously obtained for the HLS specimen with superior strength-ductility synergy.