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对热轧态与固溶处理后Fe-Mn-Al轻质高强钢进行力学性能检测及组织形貌观察,分析950~1100℃固溶处理工艺对其组织和力学性能的影响规律,根据真实应力-应变曲线和加工硬化曲线分析拉伸变形特征,对比拉伸变形前后微观组织形貌和XRD谱,研究其微观变形机理.研究结果表明,所设计的成分体系实验用钢,热轧后为奥氏体基体与少量带状铁素体的双相组织,密度为6.55 g/cm3,达到了轻质高强的设计目标.固溶处理有利于奥氏体晶粒长大与带状铁素体的破碎分解,使钢板强度降低而塑性提高,但是过高的固溶温度会促进铁素体长大,使铁素体体积分数增大,钢的断后伸长率降低.1050℃固溶处理后Fe-Mn-Al钢抗拉强度为925.9 MPa,断后伸长率为50.20%,强塑积为46.48 GPa·%.连续的应变强化行为使得Fe-Mn-Al钢获得高强度与塑性的良好匹配,稳定硬化阶段应变范围越宽,断后伸长率越大;较高的层错能使其变形机理区别于TRIP和TWIP效应,变形后仍为奥氏体+铁素体双相组织,变形后奥氏体中可以观察到Taylor晶格、高密度位错墙以及微带结构,为明显的平面滑移特征.
The mechanical properties and microstructure of Fe-Mn-Al lightweight high-strength steel after hot-rolled and solution treatment were observed. The influence of solution treatment at 950-1100 ℃ on the microstructure and mechanical properties was analyzed. According to the real stress - strain curve and work hardening curve analysis of tensile deformation characteristics before and after tensile and deformation microstructure and XRD spectrum comparison to study the mechanism of micro deformation.The results show that the design of the experimental system of steel components, The dual-phase microstructure of the matrix with a small amount of ribbon-like ferrite, the density of 6.55 g / cm3, to achieve the goal of lightweight and high strength solution treatment is conducive to austenite grain growth and ribbon-like ferrite Broken decomposition, the strength of the steel to reduce the plasticity, but too high solution temperature will promote ferrite growth, the ferrite volume fraction increases, the reduction of elongation after the steel .1050 ℃ after solution treatment of Fe The tensile strength of Mn-Al steel was 925.9 MPa, the elongation at break was 50.20%, and the strong plastic product was 46.48 GPa ·%. The continuous strain-hardening behavior made the Fe-Mn-Al steel get a good match between high strength and plasticity, Stable hardening stage, the wider the strain range, the greater the elongation after fracture; higher The fault can distinguish its deformation mechanism from the TRIP and TWIP effects, and is still austenite + ferrite dual phase after deformation. The Taylor lattice, the high-density dislocation wall and the microstrip structure can be observed in the deformed austenite , For the obvious characteristics of plane slip.