Study On Preparation And Mechanical Property Of Semi-solid B₄C/Y112 Composites

Aluminum alloy and its Composites widely used in automotive, aerospace and other fields because of its excellent properties. Among them, aluminum matrix composite material is one of the most widely used of metal matrix composite materials,but due to the preparation technology, and many other kinds of factors, its strength,elongation and wear resistance performances is not quite ideal, thus limiting its application in some areas. In this research we chose Y112 alloy as the matrix and boron carbide (B4C) as the plus reinforcement, prepared semi-solid aluminum matrix composites by mechanical mixing method. We studied the microscopic structure and mechanical property of semi-solid B4C/Y112 aluminum matrix composites affected by different preparation process and condition,and found the optimum process technology. In the same way, Y112 cast alloys and Y112 semi-solid alloys were also prepared for the purpose of performance comparison investigation.Tested the tensile, hardness and other mechanical properties of materials, and observed tensile fracture by scanning electron microscopy. The results showed that: the hardness of semi-solid aluminum matrix composites increase with the concentration of B4C particles'rasied,12wt%-B4C/Y112 composite have the highest hardness, reached 136HV. With the B4C particles contents increaseing, its tensile strength first increased and then decreased. Semi-solid composites'elongation is higher than the elongation of the cast matrix, but overall, the elongation are low. The fracture surface of semi-solid matrix composites show different morphology because of different concentration of B4C particles, mostly are brittle fracture.Dry sliding wear behaviour of semi-solid matrix and semi-solid composites were investigated by M-2000 type wear test machine, analyzing the wear abilities of composite material which contains different concentration of B4C particles, exploring the wear mechanism of the composites. The results showed that:the abrasion of the materials is the result of several kinds of wear mechanism that have comprehensive impaction; with the increase of load, The material wear rate raised gradually. Under the same condition of friction, the wear abilities of semi-solid composite material is better than semi-solid matrix, even the ability of anti-wear-out is increased by the raising percentiges with adding the B4C paticles.