热处理对6082锻造铝合金控制臂组织和力学性能的影响

发布时间：2018-03-20 03:12

  本文选题：6082锻造铝合金　切入点：热变形　出处：《长春工业大学》2017年硕士论文　论文类型：学位论文

【摘要】：随着科学技术的发展,高质量、低成本、无污染将是汽车市场竞争能力和企业经济效益提高的核心所在。而合理使用材料,尤其是汽车重要零件的材料和充分发挥材料潜力的热处理技术,将起着重要作用。汽车控制臂是将车轮受到的力传递到车身,使车轮在特定轨迹行驶的关键构件,其质量与使用者的人身安全密切相关,对刚度、强度、使用寿命的要求非常高。棒材直接机械加工件和铸造成型件的力学性能较差,不能达到控制臂的使用性能要求,因此锻造技术是主要加工方法。在铝合金锻造生产过程中,由于控制臂的形状复杂,成型比较困难,同时受铝合金成型特点的影响,其中性能不均匀(强度合格塑性不足、塑性合格强度不足)的现象比较常见,这也是目前国内外生产商所面临的共同问题。本论文以6082锻造铝合金控制臂为研究对象。首先,研究了6082铝合金的高温塑性变形行为,分析此种合金的流变应力行为随变形温度、应变速率的变化规律及内部组织结构的演变过程,评价热变形过程中变形条件对性能的影响因素,为优化此种合金挤压、轧制、锻造热加工工艺提供参考。其次,为继续提高该锻造合金控制臂的综合使用性能提供依据,探讨了固溶、时效处理对此合金微观组织结构及力学性能的影响规律。在压缩实验机(带有自制控温箱)上进行高温变形实验,得到6082锻造铝合金的真应力-真应变曲线,建立了此合金高温应力-应变本构方程及流变应力本构方程。利用金相显微镜观察了该合金高温压缩时,在一定变形温度、变形速率内微观组织结构的变化规律。结果表明,高温变形实验中,动态回复是所述锻造铝合金的主要软化机制;变形温度下降或应变速率增加,晶粒度随之增大。利用场发射扫描电子显微镜观察材料组织结构,并检测析出第二相的成分,探讨不同固溶、时效处理参数对材料微观组织与析出相的影响规律;利用XRD衍射分析仪对固溶及时效后析出相的种类进行检测;利用压缩实验机检测各个实验样品的力学性能。结果表明,组织中主要包括球状、针状的Mg2Si与棒状的AlFe(Mn)Si两种第二相;在热处理过程中,AlFe(Mn)Si相的尺寸、数量及分布不随热处理的温度及时间发生变化,对力学性能起主要作用的是Mg2Si相;固溶温度为555℃、固溶时间为2 h,空气中滞留5 s进行水淬,时效温度为170℃、时效时间为8 h是6082锻造铝合金控制臂的最佳工艺参数。
[Abstract]:With the development of science and technology, high quality, low cost and no pollution will be the core of improving the competitive power of automobile market and the economic benefit of enterprises. Especially the material of the important parts of the automobile and the heat treatment technology which can give full play to the potential of the material will play an important role. The control arm of the automobile is the key component to transfer the force of the wheel to the body and make the wheel travel on a specific track. The quality is closely related to the personal safety of the user, and the requirements for stiffness, strength and service life are very high. Therefore, forging technology is the main processing method. In the process of aluminum alloy forging, due to the complex shape of the control arm and the difficulty of forming, and influenced by the forming characteristics of aluminum alloy, the properties of the aluminum alloy are not uniform and the strength qualified plasticity is not enough. The phenomenon of insufficient plastic qualified strength) is a common problem faced by domestic and foreign manufacturers at present. In this paper, 6082 aluminum alloy control arm is taken as the research object. Firstly, the plastic deformation behavior of 6082 aluminum alloy at high temperature is studied. The rheological stress behavior of the alloy with deformation temperature, strain rate and evolution process of internal microstructure is analyzed, and the influence factors of deformation conditions on properties during hot deformation are evaluated, in order to optimize the extrusion and rolling of the alloy, Secondly, it provides the basis for improving the comprehensive performance of the control arm of the forging alloy, and discusses the solid solution. The effect of aging treatment on the microstructure and mechanical properties of the alloy was studied. The true stress-strain curves of 6082 forged aluminum alloy were obtained by high temperature deformation experiments on a compression test machine (with a self-made temperature control box). The high temperature stress-strain constitutive equation and rheological stress constitutive equation of the alloy were established. The microstructure of the alloy under high temperature compression was observed under certain deformation temperature and deformation rate. In high temperature deformation experiment, dynamic recovery is the main softening mechanism of the wrought aluminum alloy. The grain size increases with the decrease of deformation temperature or the increase of strain rate. The microstructure of the alloy is observed by field emission scanning electron microscope. The composition of the second phase was detected, and the influence of different solid solution and aging treatment parameters on the microstructure and precipitation phase of the material was discussed, and the kinds of precipitated phase after solution and aging were detected by XRD diffraction analyzer. The mechanical properties of each sample were tested by compression test machine. The results showed that the microstructure consisted mainly of spherical, needle-like Mg2Si and rod-like AlFe(Mn)Si, and the size of AlFeFeMnMn-Si phase during heat treatment. The quantity and distribution do not change with the temperature and time of heat treatment, the main effect on mechanical properties is the Mg2Si phase, the solution temperature is 555 鈩，

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