摘要本文采用不同加工参数下的搅拌摩擦加工技术（FSP）对AZ31镁合金板进行加工，研究搅拌摩擦加工对AZ31镁合金的组织、力学性能和阻尼性能的影响。采用光学显微镜、扫描电镜、XRD分析镁合金宏观形貌，微观组织演变；采用拉伸测试及硬度测试研究搅拌摩擦加工后镁合金的力学性能；采用阻尼测试技术研究搅拌摩擦加工对镁合金应变-阻尼和温度阻尼的影响。86876

AZ31镁合金经过搅拌摩擦加工后，在搅拌摩擦区宏观组织较好，没有发生明显的缺陷，并且透漏出了金属光泽。随着搅拌针旋转速度的增加，搅拌后合金表面金属光泽明显。1300,1500和1700rpm所对应的平均晶粒尺寸分别为19。52μm，20。83μm和22。65μm。镁合金经过搅拌摩擦加工以后，AZ31镁合金的抗拉强度整体下降，但是延伸率整体提高。

我们分析得出了1500rpm下搅拌摩擦加工后镁合金的延伸率，低应变阻尼值Q0-1（ε=10-4）和高应变阻尼值QH-1（ε=10-3）分别增加了121。44%, 5。02% 和7。49 % 。经过搅拌摩擦加工后的镁合金高应变阻尼值分别是0。0222，0。0264，0。02037，相比较于母材阻尼值，只有经过1500rpm的镁合金其高应变阻尼值增加7。49 %。所以当搅拌摩擦加工采用1500rpm时，AZ31镁合金获得了更好的阻尼性能。

毕业论文关键词：搅拌摩擦加工；镁合金；微观组织；阻尼性能;宏观形貌；力学性能 

Abstract In this paper, friction stir processing technology (FSP) of AZ31 magnesium alloy sheet processed to study the impact of friction stirring process on the organization AZ31 magnesium alloy, mechanical properties and damping properties。 By optical microscopy, scanning electron microscopy, XRD analysis of macro-magnesium alloy morphology, microstructure evolution; Mechanical Properties of tensile testing and hardness testing research friction stir processing of magnesium alloy; damping Testing Technology Research friction stir processing of magnesium alloy strain - damping and damping effects of temperature。

AZ31 magnesium alloy after friction stir processing and friction stir zone in the macro-organization is better, no obvious defects, and reveal a metallic luster。 With stirring increases the rotational speed of the needle, the surface of the metal alloy After stirring luster obvious。 1300,1500 and the average grain size corresponding to 1700rpm respectively 19。52μm, 20。83μm and 22。65μm。 After a magnesium alloy friction stir processing, the tensile strength of AZ31 magnesium alloy overall decline, but the overall improvement of the elongation。 Friction stir processing, the rotational speed of the mixing head can cause an increase in the temperature of the processing area is increased, the higher the processing temperature, the more obvious the recrystallization grain growth。

We analyzed the elongation at 1500rpm after friction stir processing of magnesium alloys, low strain damping values Q0-1 (ε = 10-4) and high strain damping values QH-1 (ε = 10-3), respectively, an increase of 121。44 %, 5。02% and 7。49%。 After stirring friction processing of magnesium alloy after high strain damping values are 0。0222,0。0264,0。02037, compared to the base material damping values only after 1500rpm magnesium alloy its high strain damping values increased 7。49 percent。 So when friction stir processing using 1500rpm, AZ31 magnesium alloy to obtain better damping properties。

Keyword:Friction stir processing;Magnesium alloy;Microstructure; Damping properties; Macro-morphology; Mechanical properties

目录

第一章 绪  论 1

1。1 课题研究目的及意义 1

1。2 镁合金的特点及发展前景 1