Effect of Pressure on Mechanical Properties and Microstructure During the Solidification Processing of LM6 Alloy

摘要

Solidification of metals and alloys play a vital role in the formation of desirable microstructures and hence reflects on the mechanical properties of castings. The application of pressure during solidification would be expected to affect the phase relationships in an alloy system. The purpose of this research work is to study the effect of pressure during the solidification processing of LM6 alloy castings. This paper discusses on the effect of pressure on the mechanical properties and microstructure during the solidification processing of LM6 alloy in a steel mould. From the processed castings, hardness and impact strength properties are determined and hence correlated with the microstructure. In this experimental work, 10 samples of test castings in the form of a slab are made by applying different pressure during solidification with the aid of an indigenously designed hydraulic pressure mechanism. The pouring temperature of the selected LM6 alloy material and die-preheating temperature is maintained and kept constant. Only the pressure is varied upto 38 MPa and each sample is subjected to hardness and impact strength testing for their properties determination. The microstructures of the corresponding samples are correlated with the properties and applied pressure values. From the experimental results, it is found that the hardness and impact strength properties of LM6 alloy are increased with the increased application of pressure. Besides, the grain size and its microstructural features of the castings are refined gradually with increased pressure.