Heat treatment effect on the microstructure, tensile properties and dry sliding wear behavior of A356-10%B_4C cast composites

摘要

In present paper, an attempt was made to examine the influence of T6 heat treatment (solution treatment at 540 ℃ for 5 h, quenching in hot water and artificial aging at 170 ℃ for 8 h) on the microstructure. tensile properties and dry sliding wear behavior of A356-10%B_4C cast composites. The composite ingots were made by stir casting process. In this work, the matrix alloy and composite were characterized by optical microscope, scanning electron microscope equipped with energy dispersive X-ray spectroscopy, tensile tests and conventional pin-on-disk experiment.rnThe obtained results showed that in Al-B_4C composite, T6 treatment was a dominant factor on the hardness improvement in comparison with hardness increasing due to the addition of B_4C hard particles. In addition, T6 treatment can contribute to the strong bonding between B_4C and matrix alloy and also it can change eutectic silicon morphology from acicular to near spherical. This case can lead to higher strength and wear properties of heat treated metal matrix composites in comparison with unheat treated state. Observation of worn surfaces indicated detachment of mechanically mixed layer which can primarily due to the delamination wear mechanism under higher applied load.