Study on the microstructure evolution and high temperature mechanical behaviors of the hot-rolled Ni-Al-Fe-Nb based intermetallic alloys

• Main Authors: Hung-Liang Yu, 余鴻良
• Other Authors: Sheng-Rui Jian
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/21252769857608733255

碩士 === 義守大學 === 材料科學與工程學系碩士班 === 98 === To understand the microstructure evolution and mechanical behaviors of 46.5Ni-25Al-27.5Fe-1Nb based intermetallics by hot rolled and cold rolled in some condition are the objective of this study. The original alloys were prepared by arc melting and drop casting under a argon atmosphere. For eliminating the casting stress, the samples was processed an annealing treatment with a temperature of 973K for 10 hours. And then, the sample was rolled continually by one-roller. First, the sample was put into a high furnace with a temperature of 1073K for 15 minutes and was rolled successively from 10mm to 3mm of the thickness by hot rolling, the reduction of every past is about 0.1mm .When the thickness of sample was rolled to 3mm, then the sample was rolled by cold rolling of 773K to 2mm of the thickness. After the thickness of samples were 2mm by rolling. A part of the samples were machined into tensile test specimens with the size of 3mm×2mm×20mm. Tension test was performed under Ar atmosphere by using different strain rate at different temperature (773K, 873K, 973K and 1073K). And another samples were processed by SEM, OM and micro-hardness test in order to observe the difference of structures,fracture appearance, hardness and mechanical behaviors etc.. From these tests show that 46.5Ni-25Al-27.5Fe-1Nb based intermetallics after homogenizing treatment, the hardness of matrix is higher than precipitation about 143 to 199Hv, since matrix is intermetallics β′ phase and have higher bond strength, therefore matrix is harder than recipitation .Since recipitation is solid solution of Ni, therefore it is softer than matrix. In high temperature, temperature impact lot of mechanical behaviors. In higher temperature and slower strain rate, the increase of elongation and ductility of specimens be more significantly.