Study On Plastic Deformation Of Al Matrix Composites Reinforced By Al-Fe Intermetallics

The effect of the plastic deformation on the microstructure and mechanical property of aluminum matrix composites reinforced by Al-Fe intermetallics was researched in this paper. The composites was prepared by technique of mechanical stirring, the strip-like of intensifying phase of Al3Fe distributed in the aluminum, obviously, the general mechanical property was sharply lowered. After the heat treatment, the uniformity of the distribution of intensifying phase was mended, but the size of the crystal grain still thick as before. Therefore, in order to refine the grain of intensifying phase and heightened the mechanical property of the material, the other ways should be adopted. The two ways of plastic deformation, equal channel angular pressing (ECAP) and compressing deformation, were used in this paper for those purpose. Firstly, the law of plastic deformation of commercially pure aluminum was researched in this paper. Three different routes of press were used in the experiment of ECAP of aluminum, and then, the effects of pressing routes and pressing times on the microstructure and mechanical property of aluminum were analyzed, a best technology was summarized, and there was a great value of reference for the research of the aluminum matrix composites in ECAP. Secondly, the experiment of plastic deformation of the composites was carried out with two ways of compression deformation and ECAP. The composites were broken during the experiment of ECAP. The reasons of this fracture were analyzed in the paper, there were three chief reasons, (1) brittleness of this composites was high; (2) there were many flaws in the material by the bad control in the course of smelting; (3) the pressing velocity of the hydrostatic press was too fast, because it could not be controlled. In the experiment of compressing deformation, with different velocities of compressing, the sample of these composites was deformed at different degree. Through the analysis of the effect of compressing velocity and the quantity of compressing deformation on the microstructure of composites, it was found that there was a series of fracture, passivating, warping, refining and uniformity of strip-like of Al3Fe in the course of compressing deformation of the sample, at the end, the strip-like microstructure was fractured and changed into exiguous grain-like microstructure. The result of hardness showed that the uniformity of the distribution of intensifying phase was greatly mended by compressing deformation. The different of fore-and-aft fracture were analyzed; it showed that after the deformation, the brittle fracture morphology before the deformation had been changed to plastic fracture morphology.