Precise Orientation Control of Single Crystalline NiMnGa-Based Alloys by in-situ EBSD Analysis

Abstract

the article presents a precise method for the orientation process of niMnGa-based single crystals. For this method, a scanning electron microscope equipped with an eBSD camera and a heating stage allowing temperatures exceeding 873 k was used. the orientation process was carried out in both the high-temperature austenite phase and in the room-temperature martensite phase. the facilities allowed for determining the orientation of a single grain of austenite at elevated temperatures as well as the orientation of particular martensitic variants at room temperature. A practically perfect cubic orientation was obtained in the austenitic case with a deviation of about 1° while the samples oriented in the martensitic phase deviated from the desired orientation by 4.5-5.2°. Additionally, the training process of single crystals was carried out in order to show the influence of the orientation process on twinning stress.