A study of group variants of martensite in Fe-Mn-Al-C alloy by transmission electron microscopy

[[abstract]]Martensitic transformation in a BCC matrix in duplex Fe-Mn-Al-C alloys had been studied by several researchers.( l-4) The structure of martensite was identified to be close to a long period stacking order (LPSO) structure of 18R(42),. The crystallography of martensite such as orientation relationship, habit plane, shape strain and lattice invariant shear was verified by transmission electron microscopy (TEM), and the experimental crystallography was in good agreement with the theoretical results.(4) Twenty-four crystallographic martensite variants are possibly formed in Cu base shape memory alloys.(5-8) These twenty-four varjants consist of six plate groups, each of which consists of four habit plane variants that are near to and symmetrically clustered about (01 1 } .poles of the parent phase. Variants within a single group could form diamond, folk, wedge or spear shape.(S) However, morphology and structure of martensite variants in Fe&In-Al-C alloy have not been studied intensively yet. Especially, application of high resolution transmission electron microscopy (HRTEM) in this area of study is rare so far. In this paper, we present a HREM study of group variants of martensite in an Fe-Mn-Al-C alloy. The HRTEM could reveal local structures between variants in nanometer scale which may not be detectable by conventional TE:M technique.[[fileno]]2020326010068[[department]]材料科學工程學