摘要
用快速凝固技术制备了名义成分为Ni_(53)Mn_(25)Ga_(22)的细晶合金薄带。由于快速凝固与常规的铸造方式不同,将会引起合金产生一系列的变化。通过XRD的研究表明,快速凝固使合金的室温结构发生改变;室温下,铸态合金的结构为非调制(NM)马氏体结构,而快凝薄带则为7M调制马氏体结构;快速凝固引起合金的马氏体相变温度降低,这些参数在退火后有所升高。快凝薄带弯曲变形后对其加热能够基本回复到初始形状,显示出良好的热致形状记忆效应;薄带在变形过程中不发生断裂,可见快速凝固技术显著细化了晶粒尺寸而使合金的力学性能得到明显改善,作为磁控形状记忆合金更利于实际应用。
The ribbons with nominal composition of Ni53Mn25Ga22 were prepared by melt-spun method. As melt-spun technique was different from conventional casting, a series of variation would be caused during the processing. Accounting to the XRD results, the crystal structure of the alloy at room temperature was transformed from NM martensite structure in bulk material to 7M modulated martensite structure in ribbons. Martensite transformation temperatures were decreased after melt-spun and they got a little increase after annealing. The ribbons could be bent and return to the initial shape after heating to some extent, showing a good shape memory effect. The ribbons did not rupture during be bent, which suggested that the mechanical property was improved because of refined grains from melt-spun, so it would be helpful to practical application as a magnetic shape memory alloy.
出处
《铸造》
CAS
CSCD
北大核心
2017年第7期735-738,共4页
Foundry
