柱状晶Cu-Al-Be形状记忆合金低温压缩性能研究

Low-temperature Compression Properties of Columnar Cu-Al-Be Shape Memory Alloy

利用竖直下拉式热型连铸技术制备柱状晶Cu-Al-Be形状记忆合金,其马氏体相变结束温度(Mf)在-50℃以下,柱状晶生长方向为轴向。在温度低于Mf时,对普通多晶、平行于柱状晶方向和垂直于柱状晶方向的试样分别进行单向压缩试验,并进行金相组织观察与断口形貌分析。结果发现,柱状晶Cu-Al-Be合金杆件组织结构为类似于贝壳的仿生结构且断裂形式相似,垂直于柱状晶方向的试样塑性最好,断裂前吸收能量最高,综合性能最好。

Columnar crystal Cu-Al-Be shape memory alloy rods were prepared by vertical Ohno continuous casting technology,in which the Mfwas below-50℃,and the columnar crystal growth direction presented the axial direction.The samples which are normal polycrystalline or parallel to the columnar crystal direction or perpendicular to the columnar crystal direction were compressed in single direction under a low temperature condition below the Mf.The image along the growth direction and fracture morphology of the columnar crystal were observed by optical microscope(OM)and SEM.The results reveal that the microstructure of the columnar Cu-Al-Be alloy rod is similar to that of the hierarchical structures of nacre and the fracture morphology is similar too.In addition,the sample perpendicular to the columnar crystal direction presents the desirable plasticity and the highest absorption energy before fracture,showing the desirable comprehensive performance.