حمید رضا عسگری، رضا غلامی پور، فرزاد شهری
مهندسی متالورژی
2018
In the present study, crystallization behavior of amorphous (Al90Ni8Zr2)98MM2 alloy have been investigated using X-ray diffraction, differential scanning calorimetry (DSC) and microhardness test. For this purpose, amorphous ribbons were manufactured using a melt-spinning apparatus. The average thickness of the produced ribbon was 20 micrometers. The results of the kinetic test showed that the crystallization in the amorphous alloy (Al90Ni8Zr2)98MM2 occurs at least in three steps. DSC graphs were analyzed using Kissinger's method and the activation energy for the first, second and a third stage of crystallization was 331, 241, and 330 kJ/mole, respectively. The results of micro-hardness test showed that the amorphous phase hardness at room temperature was 413 Vickers, which was reduced to 276Hv by isothermal heat treatment at temperatures close to first transformation temperatures. It has been observed that, after heat treatment at a temperature above α-Al phase transformation temperature, the hardness increases to 453Hv. Formation of intermetallic phases at 800K, cause the hardness drop to 269Hv.