振动压力下铝(镁)合金消失模铸造组织性能研究-材料加工工程专业论文.docx

AbstractLost foam casting (LFC) process has been considered as the New Foundry Technology in 21st Century and the Green Project in Foundry because of its unique advantages. In recent years, the LFC process of aluminum (magnesium) alloy has been developing rapidly, and shows its great vitality and wide application prospect. However, the main obstacles for LFC process development of aluminum (magnesium) alloy are filling ability poorer, microstructures coarser, and the pinhole, shrinkage or loose defects more serious, so the mechanical properties are lower. In order to solve above problems, the vibration and the pressure are applied on the LFC to improve the mechanical properties of aluminum (magnesium) alloy in this dissertation. The technologic theory of LFC process with mechanical vibration and gas pressure were systematical studied, and the new LFC technology of aluminum (magnesium) alloy under vibration-pressure solidification was developed, also the intensified ways of aluminum (magnesium) alloy were investigated by the means of alloying and heat treatment. Using the new LFC technology, the high strength aluminum (magnesium) alloy castings could be produced, and the best technologic parameters were obtained for the typical casting parts.A356 and AZ91D alloys LFC process with vibration solidification were researched. The results show that appropriate pouring temperatures are 730~760℃ for middle-smallsize complex castings. The vertical vibration with frequencies 30~60Hz, amplitudes 0.11~0.45mm and peak accelerations 1~4g （g=9.8m/s2）has the obviouis effect on grainsrefinement and the improvement of mechanical properties and filling ability. The tensile strengths of A356 and AZ91D as-cast alloys in LFC with vibration solidification are attained to 182MPa and 165MPa, and up by 25% and 22% over that of conventional LFC, respectively. But it could easily lead to the defects such as casting distortion, sticky sand, porosity and inclusions when the peak acceleration is g