热轧高强度V-Mo复合合金化TWIP钢的拉伸应变硬化行为  

Tensile strain hardening behavior of hot rolled high-strength V-Mo composite alloyed TWIP steel

作　　者：吴焕坤 孙挺[2] 时捷[2] 吴润[1] Wu Huankun;Sun Ting;Shi Jie;Wu Run(College of Materials and Metallurgy,Wuhan University of Science and Technology,Wuhan Hubei 430081,China;Institute for Structural Materials,Central Iron and Steel Research Institute,Beijing 100081,China)

机构地区：[1]武汉科技大学材料与冶金学院,湖北武汉430081 [2]钢铁研究总院特殊钢研究所,北京100081

出　　处：《金属热处理》2019年第1期91-95,共5页Heat Treatment of Metals

摘　　要：利用单轴拉伸试验、扫描电镜和透射电镜等研究了热轧高强度V-Mo复合合金化TWIP钢时效前后的应变硬化行为。结果表明,试验钢的TWIP效应受到抑制,在650℃时效后发生了二次硬化,抗拉强度达到1201 MPa,屈服强度达到1070 MPa,远高于一般奥氏体钢。通过Ludwigson的修正Hollomon公式计算分析发现塑性变形阶段分为两个阶段:塑性变形初期位错的滑移起主导地位,变形后期主要是形变诱导孪晶以及位错与孪生的交互作用。基于对析出相分析、计算结果和透射观察的分析,时效后纳米级(V,Mo) C析出导致了二次硬化的发生。而试验钢TWIP效应不明显,这主要与热轧后析出的大量细小弥散的碳化物抑制孪晶生长有关。Strain hardening behavior of a hot-rolled high-strength V-Mo composite alloyed TWIP steel was carried out by means of tensile tests,SEM and TEM observation. The results show that the TWIP effect of the tested steel is not obvious. After aging at 650 ℃,the hotrolled V-Mo TWIP steel occurs secondary-hardening,the yield strength reaches 1070 MPa and tensile strength reaches 1201 MPa,which are much higher than that the general austenitic steel. The plastic deformation stage is mainly divided into two parts after being calculated by Hollomon formulas modified by Ludwigson. In the early stages of plastic deformation,dislocation slip plays a dominant role,but the main deformation mechanism will be twining induced plasticity and interactions between dislocations and twins in the second stage. Based on the analysis of the precipitated phase,calculation results and TEM observation,it is found that there is nanoscale( V,Mo) C precipitation in the steel after aging at 650 ℃,which is consistent with the observations by TEM. Moreover,it is found that the large amount of finely and dispersed carbides precipitation after hot rolling,which is the main reason of the TWIP effect of experimental steel is not obvious.

关 键 词：热轧 孪晶诱导塑性 高强度 碳化物 

分 类 号：TG146.2[一般工业技术—材料科学与工程]