AZ31镁合金板状坯材挤压参数研究.doc

毕业论文 AZ31镁合金板状坯材挤压参数研究 摘　　要 本论文针对AZ31镁合金板状坯材挤压参数进行了研究，并进一步研究了镁合金在不同温度条件下挤压比、挤压速度和压力等参数的关系，优化加工参数，为工业加工、处理等生产应用方面奠定了基础。 AZ31镁合金进行一定的热挤压后抗拉强度和伸长率得到了有效的提高。研究结果表明，热挤压过程中影响镁合金板材组织及力学性能的因素主要有温度、挤压速度及挤压方式和挤压比。挤压过程中，随着加热温度的升高，发生部分回复和再结晶行为，随位错密度降低，局部晶粒细化，镁合金板材抗拉强度下降，伸长率显著提高。而变形速度影响孪生的形核与长大，变形速度越慢,越有利于孪生的形核与长大,试样的屈服强度和极限抗压强度越高,变形量越大。最后，随着挤压比的增加,晶粒尺寸进一步减小,合金的抗拉强度和屈服强度得到明显提高，但当挤压比增大到一定值时,伸长率的增加幅度减缓。 关键词：镁合金 挤压参数 显微组织 性能 挤压比 ABSTRACT In this thesis， study the AZ31 magnesium alloy plate-like billet extrusion parameters of the study,And further study the relationship of magnesium alloy at different temperatures,different conditions of extrusion ratio,extrusion speed and pressure parameters,optimization of processing parameters.Used for the industrial processing,handling and other production applications,laying the foundation. After hot extrusion the tensile strength and elongation of AZ31 magnesium alloy have been effectively improved.The results show that,the the main factors of impact hot-extrusion process of magnesium alloy sheet and mechanical properties are temperature, extrusion speed and extrusion method and extrusion ratio. In extrusion process, As the reasing of heating temperature, Partial recovery and recrystallization behavior happened, With the dislocation density decrease, local grain refinement, tensile strength of magnesium alloy sheet decreased, elongation significantly increased. The deformation speed also impact the growth of twin nucleation,Slower deformation, The more beneficial to twin nucleation and growth, the higher yield strength and ultimate compressive strength of Sample, The deformation will greater.At last, With the increase of extrusion, The grain size further decreases, Tensile strength and yield strength has been markedly enhanced, But when the extrusion ratio increases to a certain value, Elongation rate of increase slowed. Keywords: Magnesium Extrusion Parameters Microstructure Performance Extrusion ratio 目　　录 第一章　　前言 1 1.1镁及镁合金的特点 1 1.