Effect of electropulse modification parameters on ingot macrostructure of Cu-Al-Ni shape memory alloys

In order to improve ingot structure and to refine grain size of Cu Al Ni shape memory alloys by means of electropulse modification, the effect of voltage, frequency and time of the pulse as well as the type of cooling mold on the macrostructure of ingot have been systematically studied. The results show that the above four parameters are important influencing factors on the ingot macrostructure. By appropriately adjusting the parameters, the macrostructure of polycrystalline Cu Al Ni ingot can be significantly improved and nearly fully equiaxied region of the ingot is obtained; the corresponding grain size of the ingot can be dramatically reduced to less than 1/20 of that of unmodified.