Effect of powder mixing on the mechanical strength of polyamide 6-AZ61 magnesium composites prepared by compression molding

A composite material of polyamide 6 and AZ61 magnesium alloy was produced by hot press molding. Both matrix and reinforcement powders were thoroughly mixed by ball milling and then hot pressed to forge a bulk material. Four process parameters of the mixing process including milling time, milling speed, ball-to-powder weight ratio, and the AZ61 wt percentage at various levels were investigated for their influences on the mechanical strength of the composites. Material characterization includes XRD, scanning electron microscopy, uniaxial tensile test, and Vickers hardness. An experimental design using Taguchi (L9 (3,4)) and an analysis of variance indicate that the AZ61 wt percentage is the most influential factor in the ultimate strength of the PA6-AZ61 composite. Adding 5 wt% reinforcement powders to PA6 and milled at 300 rpm for 30 min can increase the average ultimate tensile strength of composites to 63.83 MPa with a maximum strain of 7.71 %, and Vickers hardness of 21.97 HV. As compared to those in the pure PA6 matrix (58.83 MPa 2.29 %, and 13.01 HV), this enhancement in ductility is achieved by the well-dispersed AZ61 particles in the PA6 matrix.