Effect of sintering mechanisms on mechanical properties of AA7075/B4C composite fabricated by powder metallurgy techniques

Abstract

Abstract Metal matrix composites gain massive demand in the industrial sector because of their superior properties compared to alloys. The present work focus on the fabrication of the AA7075/B4C micro composite subjected to different sintering techniques. Fabrication techniques involve, ball milling of boron carbide powders, to reduce its size from 50 microns to 10 microns. Mixing of B4C powders with AA7075 alloy powders was carried out in the ball milling machine with 6% B4C as reinforcement composition, followed by cold compaction, and then sintering happened using three techniques namely, conventional sintering, spark plasma sintering, and microwave-assisted sintering. The microstructural investigation was carried out under SEM integrated with EDS to determine the distribution of reinforcement particles and characterization of fabricated samples. Tensile, compression, and hardness tests were conducted to examine the effect of sintering techniques. Results showed superior enhancement in the mechanical properties in spark plasma sintered composites compared to other sintering processes as it sinters in significantly less time, and at low temperatures. Microwave sintered composite has shown excellent mechanical properties because of its low sintering time and temperatures. The conventionally sintered composite showed inadequate mechanical responses because of their high-temperature processing and time, intermetallic compound formation, high porosity levels. Among the adopted three sintering techniques, spark Plasma sintering gave the best mechanical properties to the composite materials and high strain to fracture values.