【作者】 高丹；

【导师】 邓子玉；

【作者基本信息】 沈阳理工大学 ， 材料加工工程， 2008， 硕士

【摘要】 镁合金是所有金属结构材料中最轻的,其密度通常在1.75×10~3~1.85×10~3kg/m~3,是铝的2/3 ,钢的3/4。镁合金具有很高的比强度和比刚度,己被誉为21世纪的金属。但由于镁合金的晶体结构为密排六方,塑性不及较常用的面心立方结构金属,塑性成形能力差,因而镁合金在压铸成形领域优先得到重视和发展。变形镁合金与铸造镁合金相比,有更优良的综合性能,因而为了推动镁合金在航空、航天、汽车、摩托车等领域内的大量应用,发展我国的镁工业,必须大力开发变形镁合金及其生产工艺。本研究是在全球轻量化、大力发展镁合金的背景下,以镁合金ZK60为研究对象,对ZK60镁合金的高温流动行为进行了系统研究,确定出了ZK60镁合金高温变形时的最佳工艺参数范围;以ZK60镁合金高温变形的应力-应变曲线的特征分析为基础,建立了ZK60镁合金高温变形时的流动应力模型。验证结果表明,ZK60镁合金高温变形时的流动应力模型能较好地描述合金的高温变形行为。同时研究分析了ZK60镁合金的组织变化及动态再结晶。应用有限元方法,对锻造充型实验进行了数值模拟。着重讨论了不同的凸模斜度、圆角半径对变形过程的影响。研究结果表明,采用合理的凸模斜度和圆角半径,可避免锻造过程中的应力集中现象;镁合金在凸模斜度为3°,圆角半径为2mm的条件下锻造时具有更好的流动性和较低的变形抗力。上述研究为ZK60镁合金锻造工艺的优化设计及质量控制提供了理论和技术上的支持。更多还原

【Abstract】 Magnesium alloys is the most light in all of the metal construction materials,its density only contain 1.75×103~1.85×103kg/m3, its density is 2/3 than that of aluminum, 1/4 of steel.The magnesium alloy has high specific strength and specific rigidity.The magnesium alloy will display important roles in the 21st century.Because of close-packed hexagonal structure,its plasticity displays worse than aluminum, as a result magnesium alloy at die-casting forming realm are attached importance and develop. Forming magnesium alloy have the more synthetical capability than the casts magnesium alloy, as a result for pushing the magnesium alloy in aviation, car, motorcycle...etc realm more be applied, For developing the magnesium industry of our country, must strongly develop forming magnesium alloy and its production crafts.This background of research is global lightweight and developing the magnesium, choose ZK60 magnesium alloy proceeds the research, Based on the characteristics of the stress-strain curves of the ZK60 magnesium alloy during high temperature deformation, the flow stress model of ZK60 magnesium alloy during high temperature deformation has been established by the isothermal compression. Meanwhile, the present model is checked. It is proofed that present constitutive relationship has a good reliability. In addition, studying systematically the regulation of organize evolvement and dynamic recrystallization of ZK60 magnesium alloy during heat forming.The effects of parameters in forging like cavity die-filling have been numerically simulated by finite element method. The affect of emphatically the different inclination of drift and punch-nose radius for equivalent strain, stress and load-journey curves have been discussed. The results investigated show that when adoption of the inclination of drift is 3°and the punch-nose radius 3mm, the magnesium alloy has better flowing ability and lower forming resistance. This work provides the theory and technique foundation for implementing process optimized design and quality control scheme of ZK60 magnesium alloy connecting piece isothermal forging process.更多还原