Polycrystal Niti Shape Memory Alloy Grain And Grain Boundary Deformation Experiment Research

NiT（iNitinol）shape memory alloy is widely used in kinds of fields today. With thedevelopment of micro machine and information technology, the material plays moresignificant role in material processing. Because of its superiority and characteristic, theresearchers are more interested in deformation characteristics of this kind of material inmicro scale, which reveals the feature inside crystalline grain and grain boundary underloading and interrelationship of grains,in order to study further on micro mechanism andlay a foundation for establishing the model of microscopic theory.In this paper, the theory and experimental procedure of Digital Image CorrelationMethod (DICM) are introduced first. For the sake of processing surface of NiTi shapememory alloy, we proposed a new polishing method Combined with mechanicalpolishing and electrochemical polishing. Making use of this method, metallographic canbe gained perfectly under metallographic microscope and scanning electron microscopy(SEM).Last,the crystalline grain deformation of NiTi shape memory alloy was observedand recorded under tensile loading by SEM. The experimental result indicates: Thoughcrystalline grain deforms largely, grain boundary still coordinates well. Otherwise, thesize of grain influences mechanics characteristic of this material in a way.