Study of the Mechanical Milling Process of AZ91D Magnesium Alloy Chips and Mechanical Alloying of Obtained Powder with Silicon Carbide Particles

In this research, the mechanical milling process as an effective recycling method in preventing the waste of raw materials and energy consumption was used to produce powders from the AZ91D magnesium alloy chips with average size of 4 2 1 (mm) in a planetary ball mill. The powders obtained were mechanically alloyed with 70 wt.% (57 vol.%) silicon carbide of two coarse and fine sizes by the same apparatus. The simultaneous effect of mechanical milling and alloying parameters (time, ball to powder ratio) on the produced powders were investigated by a field emission scanning electron microscopy (FESEM) and particle size analyzer (PSA). Powder yield was also determined in milled powders as one of the most important indicators to estimate the amount of powders obtained after ball milling. The results show that in the mechanical milling process, by choosing the high ball to powder ratio, smaller particle size, higher yield and more uniform distribution of composite particles can be achieved at lower milling times. The best result was obtained for the mechanical milling in the condition of 10-hour milling with a BPR 25:1, and for mechanical alloying, Both for the 2-micron and 238-micron carbide particles, in condition of 5-hour milling with a BPR 20:1. X-ray diffraction (XRD) patterns of chips and powders obtained mechanical milling and alloying indicate that there is no unwanted phase in these processes.