中文摘要：

采用单辊快淬法制备了名义成分为Ni43Co7Mn41Sn9的高温形状记忆合金薄带，并对其微观组织结构和马氏体相变进行了研究．结果表明，薄带发生一步热弹性马氏体相变，经高温热处理后马氏体相变温度达到160℃．制备态薄带的晶粒为微米级，大小不一，介于2-18μm之间，与块体母合金相比晶粒明显细化，且大部分晶粒沿垂直薄带表面方向生长．室温下，薄带（消除内应力后）为正方结构的非调制马氏体，马氏体变体内部由孪晶亚结构组成．热处理后薄带的相变温度有所下降，但随着热处理温度的升高基本保持不变．

英文摘要：

NiCoMnSn shape memory alloy （SMA） is expected to be a promising high temperature SMA. However, the brittleness has become a big obstacle for its practical application. It is known that, grain refining is effective in improving the ductility of a specific metallic alloy. The aim of this work is to investigate the effect of melt-spinning on grain refinement and martensitic transformation and provide a guideline for the development of NiCoMnSn SMA. Ni43CoTMn41Sn9 high temperature SMA ribbon was prepared by a single roll melt-spinning method. The microstructure and martensitic transformation were investigated by means of OM, SEM, TEM, XRD and DSC, respectively. The experimental results showed that, the ribbon had a chemical composition close to the master alloy and exhibited a thermoelastic martensitic transformation at about 160 ℃ The grains in the as-spun ribbon, ranging from 2 μm to 18 μm, were remarkably refined compared with the master alloy. In the as prepared ribbon, most of the columnar grains grew along the direction vertical to the ribbon plane. At room temperature, non-modulated martensite （tetragonal structure） consisting of twin substructure is determined in the ribbon after relieving the internal stress. Transformation temperatures were lowered by 30℃ after heat treatment at 400℃ for 1 h and then kept nearly constant with the increase of heat treatment temperatures.