设计了一种低应力下容易发生ε马氏体转变的Fe-17Mn-6Si-0.3C高Si高Mn钢. 采用OM, XRD和TEM研究了高Si高Mn钢和传统高Mn钢在静态拉伸和动态冲击时的力学性能及组织演化. 结果表明: 静态拉伸下高Si高Mn钢比传统高Mn钢具有更高的加工硬化速率; 动态冲击下高Si高Mn钢的表面硬度高于传统高Mn钢, 而冲击变形量却显著低于传统高Mn钢.高Si高Mn钢变形时应力诱发ε马氏体转变的优先发生是导致上述结果的原因. 这个结果间接证实了传统高Mn钢的异常加工硬化能力来源于形变孪晶的形成及其因C原子存在导致的严重晶格畸变.

There exist poor work hardening capacity under medium or low stress condition in conventional Hadfield steels. This poor work hardening capacity together with their low yield strength result in a serious plastic deformation in initial service. To address these two problems, a mechanism had been put forward to explain the unusual work hardening ability of conventional Hadfield steel under heavy stress or high load impact. The formation of deformation twins and its concomitant serious lattice distortion is responsible for their unusual work hardening ability due to the existence of interstitial C atoms. Based on the fact that the same effect can be produced after the formation of stress–induced " martensitic transformation, a high silicon high manganese steel Fe–17Mn–6Si–0.3C was designed. In this alloy the stress–induced " martensitic transformation easily took place under low stress. The mechanical properties and microstructure evolution of the high silicon high manganese steel and a conventional Hadfield steel were studied by OM, XRD and TEM under both static tension and dynamic impact loads. The results showed that under the tension load the high silicon high manganese steel had higher strain hardening rate than the conventional Hadfield steel. Under dynamic impact load the high silicon high manganese steel had lower impact deformation but higher surface hardness than the conventional Hadfield steel. The preferential occurrence of stress–induced " martensitic transformation accounted for this difference. This result also indirectly confirmed that the formation of deformation twins and its concomitant serious lattice distortion due to the existence of interstitial C atoms led to the unusual work hardening ability of conventional Hadfield steel.