Microstructural and Crystallographic Insights in a Martensite/Austenite Dual Phase Ni–Mn–Sb Alloy

Abstract

For Ni-Mn-Sb multifunctional alloy, its microstructure and crystallographic information are decisive factors for its multiple magnetic field induced properties, such as magnetic field induced shape memory effect, magneto-caloric effect, exchange bias effect, and so on. While, studies on such field are rarely conducted. In the present work, a comprehensive study on microstructural features and crystallographic characteristics has been conducted in a martensite/austenite dual phase coexisting polycrystalline Ni 50 Mn 37 Sb 13 alloy. Results show that the martensite is self-organized in plates in the original austenite. The intra-plate martensite presents a fine lamellar microstructure and each fine lamella corresponds to one martensite variant. Crystallographic orientation analysis indicates that each martensite plate exists four differently oriented martensite variants and they can form three types of twins, type I, type II, and compound twin. Trace analysis results show that the interface between adjacent variants are their twinning plane K 1 . Further investigation on martensitic transformation orientation relationship reveals that the Pitsch orientation relationship, specified as 0 1 1g A È // 2 2 1g M È and < 0 11> A //< 1 22> M , is the effective one from austenite to martensite. All the above results offer basic microstructural and crystallographic information on Ni-Mn-Sb alloys and can be useful for further investigation on property optimization of these alloys.