热循环对Fe—23Mn和Fe—28Mn—4Si合金马氏体相变和组织结构的影响

Effect of Thermal Cycling on the Martensitic Transformation and Microstructure of Fe- 23Mn and Fe-28Mn-4Si Alloys

Ｆｅ—２３Ｍｎ合金和Ｆｅ—２８Ｍｎ一４Ｓｉ合金的马氏体相变在热循环中的行为截然相反，Ｆｅ—２３Ｍｎ合金奥氏体经热循环后产生稳定化，随着热循环次数增加，ε马氏体数量减少直至消失，得到单相奥氏体组织．但热循环稳定化的奥氏体在室温时效过程中发生等温γ→ε相变．Ｆｅ—２８Ｍｎ一４Ｓｉ合金奥氏体经热循环后不产生稳定化，ε马氏体数量不是减少，而是明显增多．Ｆｅ—２８Ｍｎ一４Ｓｉ合金γ→ε相变具有组织遗传特征，而Ｆｅ—２３Ｍｎ合金没有组织遗传特征．

The effecd of thermal cycling on γ→εmartensitic transformation in Fe-28Mn -4Si alloy and inFe-23Mn alloy is different.The austenite of Fe-23Mn alloy is stabilized aha Cyclic transfomation against the subsequent γ→ε martensitic transformation and the structure become fully austenite atroom tempeature after 5 thermal cycles.The austerity stabilzed by thermal cycling transfers isothermallyinto εmertensite when it is tempered at room temperature. However,the austenite of Fe-28Mn-4Sialloy is not stabilized and the γ→εmartensitic transformtion is enhanced by thermal cycling.The microstructure reco very is observed in Fe-28Mn-4Si alloy,but it is not observed in Fe-23Mn alloy.