The Study Of Al-Mo-Re（Gd,Ho） Ternary Phase Diagram And Comprehensive Properties Of Er, B Microalloying Mg₂Si Reinforced Aluminum Alloy

As a nonferrous metal structure material which is the most widely used in industry, the aluminum alloy has a profound research value. At present, the study of aluminum alloy is mainly divided into two aspects of basic scientific research and practical performance research. This thesis makes a preliminary exploration about aluminum alloy phase diagram and the alloy microstructure and mechanical properties of Mg2Si reinforced aluminum alloy.The study of aluminum alloy diagram based on Al-TM-RE system. Al-TM-RE alloys have attracted extensive attention due to its potential amorphous forming ability and outstanding mechanical properties. It is possible for the Al-TM-RE alloys to be the structural metallic materials with the highest specific strength because of their light weigth, high strength and high tenacity. The isothermal section of the Al-Mo-RE (Gd, Ho) ternary phase diagrams at 773 K which belong to Al-TM-RE systems have been researched mainly by means of CARL ZEISS microscope, scanning electron microscopy, energy disperse spectroscopy and X-ray powder diffraction respectively in this topic. According to the experimental results,10 binary phases exist in the isothermal section of Al-Mo-RE (Gd, Ho) ternary system at 773 K, namely:AlMo3, Al8Mo3, Al17Mo4, Al12Mo, Al5Mo, AlRE2, Al2RE3, AlRE, Al2RE and Al3RE. Two ternary compounds Al43Mo4Gd6 and Al4Mo2Gd have been confirmed in the Al-Mo-Gd system. In Al-Mo-Ho system, in addition to the confirmation of the AI43Mo4Ho6 ternary phase, the new ternary compound Al4Mo2Ho has been found. The solid solubility is determined by the phase-disappeared method at 773 K, and the results show that the maximum solid solubility of Al in Mo is to be 16.0 at.%, the solid solution range of AlMo3 is to be 21.0 at.%Al to 28.5 at.% Al and the solid solution range of Al8Mo3 is to be 72.0 at.%Al to 73.0 at.%Al. Moreover, At 773 K, the existence of controversial phases Al17Mo4 and Al4Mo have been determined experimentally, the results show that the Al]7Mo4 occur at 773K while the Al4Mo do not.In this thesis, the study of aluminum alloy properties is on the basis of Mg2Si reinforced aluminum alloys. Through the use of CARL ZEISS microscope, scanning electron microscopy, energy disperse spectroscopy, X-ray powder diffraction and vickers hardness tester, We study the influence of the addition of Er elment associace with B element and the heat treatment system on the micromorphology, hardness, tensile strength of the 6063 aluminum alloys, and our experimental results show that when the addition of Er element reaches to 0.5 wt.%and B element reaches to 0.1 wt.%, best comprehensive mechanical properties can be obtained for the 6063 aluminum alloys. The optimal solid solution treatment system for the 6063 alloy is heated at 560 ℃ for 24 hours.Through the use of CARL ZEISS microscope, scanning electron microscopy, energy disperse spectroscopy and X-ray powder diffraction, We study the influence of the addition of Er element and cooling rate on the micromorphology of the Al-15 wt.% Mg2Si alloy, and our experimental results show that when the addition of Er element reaches to 0.6 wt.%, best microstructure can be obtained for the Al-15 wt.% Mg2Si alloy.in the case of water cooling.