【作者】 徐晨；

【导师】 陈国香； 闫洪；

【作者基本信息】 南昌大学 ， 材料加工工程， 2006， 硕士

【摘要】 半固态成形技术兼有液态和固态金属成形的优良特性，是高效、节能的材料加工前沿技术，是21世纪最具有发展潜力的金属成形技术之一。 本文采用基于刚塑性／刚粘塑性有限元方法对镁合金汽车中间轴螺塞的成形过程进行数值模拟，并对两种不同成形工艺进行分析对比，得到了变形流动规律和力能参数。 从数值模拟结果中可以看到，圆坯料一次成形方案尽管能够减少工序，但该方案存在较大的成形缺陷。与圆坯料一次成形方案比较，预锻一终锻加工方法成形力较低，应变分布均匀，不易产生成形缺陷和应力集中。 采用基于刚粘塑性有限元方法对镁合金触变锻造过程进行数值模拟。利用基于多元非线性回归方法建立的半固态AZ61合金本构关系确立了相关模拟参数，并分析了高固相体积分数下半固态镁合金材料触变力学性能，得到镁合金零件半固态触变成形过程的变形流动规律和温度场。 结果表明，半固态镁合金材料较常规态材料变形抗力小，成形载荷有较大降低。半固态成形零件等效应力分布较为合理，而常规态材料易产生应力集中，需要补充后续加工工序。在接近固相线温度下，半固态成形的材料充填性能与常态的差别不大。 采用半固态模锻的方法对Y112铝合金进行触变成形试验。用机械搅拌制出半固态坯料，并对搅拌前原始枝晶坯料和半固态坯料进行了微观组织分析及对比。二次加热实验表明Y112铝合金液相线铸造坯料在565℃左右保温15-30min 能够获得较满意的适于半固态成形的触变组织。 Y112铝合金高固相率半固态模锻过程数值模拟中变形力要略小于真实试验中变形力，数值和变化趋势二者基本吻合。同时数值模拟结果表明半固态触变成形后零件中应力应变分布均匀，半固态技术较传统加工方式具有优越性。更多还原

【Abstract】 As a energy conservation, high efficiency material processing technology, semi-solid metal forming (SSM) combines the superior property of liquid and solid metal forming, is considered as the most potential one for metal forming in the 21st century.The forming process of Magnesium Alloy automobile intermediate shaft plug is analyzed with computer numerical simulation which based on rigid plastic/rigid viscoplastic finite element method, two kinds of forming process have been compared, and behavior of metal flow and Load-Stroke curve were obtained from the simulationFrom simulation results it’s concluded that though working procedure could be reduced in round-blank forming, significant form limitation occurred in this case. And compared to it, there is lower load, more uniform strain distribution and less shaped bug and stress concentration in perform-finish forging procedure.The thixo-forming process of Magnesium Alloy automobile intermediate shaft plug is analyzed with computer numerical simulation which based on rigid plastic/rigid viscoplastic finite element method。 Parameters for simulation were chose on the condition that constitutive relationship for AZ61 alloy was established by our group using multiple nonlinear regression method. Thixo mechanical properties of semi-solid AZ61 alloy in high solid fraction was also analyzed. Behavior of metal flow and temperature field were obtained from results, which was also compared with experimentation data.Results showed that forming resistance in semi-solid Mg alloy is lower than normal material, forming load is reduced sharply. The effective strain distribution in semi-solid part are more reasonable, and stress concentration more liable occurred in normal material and more procedure should be added. In temperature approached to solid-phase line, there has little difference in filling behavior between semi-solid material and normal material.更多还原