Growing Fe-Mn-Al-Ni single crystals by combining directional annealing and thermal cycling

Abstract

In pseudoelastic alloys, a fine-grained microstructure implies restrictions on the propagation and shrinkage of the martensitic phase. Thus, the pseudoelastic effect is adversely affected. For this reason, thermomechanical methods that accelerate grain growth are sought in these alloys. In this paper, we present a novel and extremely fast method to obtain single crystals of centimeter-order lengths. The process consists of combining two methods of abnormal crystal growth: directional annealing; and thermal cycling. This technique is applicable to pseudoelastic alloys that have a parent single-phase high-temperature region and a two-phase, low-temperature region. The crystallographic orientations measured in single crystals generated by this process are also shown. A full-strain recovery pseudoelastic behavior was observed in single crystalline specimens tested under compression.