The composition of martensite transformation in NiAl alloy is determined using pure nickel and aluminum powder by vacuum hot press powder metallurgy, which is a composition of martensitic transformation, and the characteristics of martensitic transformation and microstructure of sintered NiAl alloys are investigated. The produced sintered alloys are presintered and hot pressed in vacuum; after homogenizing heat treatment at 1,273 K for 86.4 ks, they are water-cooled to produce NiAl sintered alloys having relative density of 99 % or more. As a result of observations of the microstructure of the sintered NiAl alloy specimens quenched in ice water after homogenization treatment at 1,273 K, it is found that specimens of all compositions consisted of two phases and voids. In addition, it is found that martensite transformation did not occur because surface fluctuation shapes did not appear inside the crystal grains with quenching at 1,273 K. As a result of examining the relationship between the density and composition after martensitic transformation of the sintered alloys, the density after transformation is found to have increased by about 1 % compared to before the transformation. As a result of examining the relationship between the hardness (Hv) at room temperature and the composition of the matrix phase and the martensite phase, the hardness of the martensite phase is found to be smaller than that of the matrix phase. As a result of examining the relationship between the temperature at which the shape recovery is completed by heating and the composition, the shape recovery temperature is found to decrease almost linearly as the Al concentration increases, and the gradient is about -160 K/ at% Al. After quenching the sintered NiAl alloys of the 37 at%Al into martensite, specimens fractured by three-point bending at room temperature are observed by SEM and, as a result, some grain boundary fractures are observed on the fracture surface, and mainly intergranular cleavage fractures.

소량의 misch metal과 Zr을 함유한 CuZnAI형상기억 합금의 변태온도에 미치는 열사이클 및 기계적 성질 변화에 대하여 고찰하였다. 합금원소 첨가에 따라 결정립에 매우 미세화 되었으며 용체화 처리후 100~350˚C구간에서 경도값 변화를 조사하기 위하여 post quench aging과 step quench aging처리한 결과 200˚C와 250˚C에서 최고의 경도값을 나타냈다. Mf온도이하에서 인당시험한 결과 파단강도와 연실율은 결저립이 미세할수록 증가하는 경향을 보였다. 또한 파단강도는 as quenching처리한 경우보다 post quench aging처리한 경우에 보다더 증가하였다. β-상에서의 시효는 Ms온도를 강하시켰으며 마르텐사이트상에서의 시효는 As 온도를 증가시켰다. post quench aging 에 따른 As의 변화는 β에서의 회복율에 기여하였으며 변태온도 (As-Ms)히스테리시스는 열사이클에 의하여 증가하는 경향을 보였다.