Study On Preparation And Properties Of Powder Metallurgy Al-Cu-Mg-Si Materials

Powder metallurgy aluminum alloys have the properties of low density, high strength, and good corrosion resistance, which meet the urgent needs of current and future automotive lightweight. Powder metallurgy aluminum alloys have broad application prospects. In this thesis, the AMB2712powder (Al-3.8Cu-1.OMg-0.75Si system alloy) of United States USM company was studied through the analysis of the powder and the sintering process. A reasonable good performance sintered aluminum alloy was developed. Effect of sintering process on microstructure and mechanical properties was also studied. A domestic powder which has good sintered properties was developed. Conclusions are as follows:1. The results of powder texts show that AMB2712powder is a mixture of Al powder, Al-Cu alloy powder, Al-Si alloy powder, other alloy powders and lubricant. The powder particle size distribution is wide, and the powder has good Mobility. After pressed by300MPa, the density of green body is2.60g/cm3(relative density of95%).2. After sintered in the high-purity nitrogen, high purity argon, hydrogen and high purity ammonia decomposition, it was found that high-purity nitrogen atmosphere is the best sintering atmosphere. The sample is compact and mechanics best performance after sintered in high-purity nitrogen. The samples expanded in other sintering atmospheres, which made the samples have low density and poor mechanical properties.3. It was found that after sintered at different temperatures, the performance of sintering billet first increased and then decreased. During sintering at590℃, the liquid phase could fill the pores better, so that the sample achieved the best performance after sintered at590℃.4. Through the research of other parameters, the best sintering process was formulated. In the high-purity nitrogen atmosphere at a heating rate of10℃/min from room temperature to400℃, heat60min, then heating rate10℃/min was heated to590℃, holding60min, furnace cooling to200℃. then air cooled to room temperature. The density of samples under this condition was2.66g/cm3(relative density of97%), with hardness23HRB, tensile strength of205MPa and dimensional shrinkage of1.65%. 5. A powder which has similar performance with AMB2712powder was created in this research. After sintered at620℃, the sample has a uniform and dense microstructure. The density of this sample could achieve at2.65g/cm3, with a tensile strength of165MPa, hardness20HRB. The properties measured up to more than80%of AMB2712powder.