Manufacturing A356 Aluminum Alloy/Hexagonal Boron Nitride Composite and Evaluation of its Mechanical Properties

In the present investigation, a metal matrix composite consisting of A356 aluminum alloy matrix has been produced by the addition of boron nitride powder with three different conditions, i.e. raw powder, coated powder using Ni-P electroless bath and coated aluminum particles with Ni-P/BN surface composite. Moreover, parameters such as impeller shape and rotation speed have been examined in order to obtain their optimized conditions. Tensile and hardness measurement tests were carried out to choose the composite sample with superior mechanical properties. Surface of the powders were analyzed by EDAX. In addition, surface of the coated powder and the fractured surface of composite samples were examined using scanning electron microscope (SEM). The results showed the optimum value of added powder to be 6% after being coated on aluminum particles using the Ni-P electroless bath. Furthermore, the agitator of four-blade type with a radial flow was found to be a good choice for the manufacture of aluminum/boron nitride composite. It was shown that unlike single phase alloys, tensile strength of composite materials is not proportional to their hardness, e.g. a decrease in the tensile strength may cause an increase in the hardness of the composite.