금속 재료의 국부 변형 거동 분석 방법과 연구 동향: 리뷰

The behaviour and performance of complex metallic materials (e.g., advanced high strength steel and dual phase Ti alloys) are acknowledged to be multi-scale in nature and to rely on the details of the threedimensional morphology, chemistry and crystallography at the meso-scale level and on macro-scale level geometry and boundary and loading conditions. As those materials often contain a multi-phase and complicated microstructure, it is difficult to fully characterise a material’s deformation behaviour with conventional macro-scale testing. Recently, a small-scale testing method has been developed to investigate the local deformation behaviour of metallic materials based on the following core techniques: portable nanoindenation platform for providing a high resolved load-displacement system, focused ion beam (FIB) for fabricating a small-scale geometric specimen and electron backscatter diffraction (EBSD) for characterising microstructure and crystallographic orientation. This method has been combined with further high resolution techniques including HR-EBSD and X-ray micro-Laue diffraction, providing us a rich understanding of the fundamental behaviour of materials on the level of the individual microstructural constituents and potentially strengthening our understanding of materials by relating macro- and micro-scale behaviour. In this review article, we describe the small-scale testing method and further high resolution techniques used to studying complex metallic materials. (Received July 16, 2018; Accepted July 25, 2018)