Mg-Gd镁合金半固态坯料制备及模锻成形研究

发布时间：2018-05-29 22:19

  本文选题：Mg-Gd镁合金 + 等温处理　； 参考：《哈尔滨工业大学》2017年硕士论文

【摘要】：镁是在所有实用结构材料中属于比重相对较小的金属,主要以镁元素组成的镁合金其性能极其优异。目前,镁合金有很多成形方法,压铸、挤压成形和固态锻造都有他们的局限性。因此,半固态金属加工技术的出现解决他们的问题,该工艺具备了铸锻工艺的综合优点。本文就是通过对Mg-Gd镁合金棒材进行半固态等温处理和半固态等温压缩方法分别研究其组织演变规律和力学行为变化,采用模锻成形的工艺方法进行L型件模锻成形并了解L型件的微观组织变化和力学性能。通过Mg-Gd镁合金半固态等温处理及模锻成形研究,确定Mg-Gd镁合金最优的半固态坯制备参数,确认采用模锻成形工艺方法对材料的成形效果,确定一条工艺简便、成本低、材料热物理性能高的Mg-Gd镁合金零件加工途径,促进半固态模锻技术在Mg-gd镁合金成形技术上的应用。半固态等温处理实验,首先通过DSC测试该材料的半固态温度区间,在固液相温度区间内选取不同温度。然后在不同保温时间下进行等温处理,借助扫描电镜和图像分析软件等检测手段,来研究该材料半固态组织的演变规律。最终通过分析表明通过半固态等温处理,可以获得晶粒细小、球化程度好而且晶粒尺寸均匀的半固态组织。通过半固态等温压缩实验研究该材料在半固态等温压缩下力学行为。研究发现Mg-Gd镁合金在半固态下,它的变形抗力较低,变形过程中的协调能力好,而且在半固态下的Mg-Gd镁合金具有变形温度和应变速率的敏感性。最终,通过生产性的工艺实验,采用模锻成形工艺,并以L型件为具体制件,在压力机上成功制造出了L型件。并测试力学性能和观察其微观组织,并进行了分析研究。
[Abstract]:Magnesium is a relatively small proportion of metal in all practical structural materials. Magnesium alloys, mainly composed of magnesium, have excellent properties. At present, magnesium alloys have many forming methods, die-casting, extrusion forming and solid forging, so their problems are solved by the appearance of semi solid gold processing technology. In this paper, the microstructure evolution and mechanical behavior change of Mg-Gd magnesium alloy bar are studied by semi solid isothermal treatment and semi solid isothermal compression method. The forging process of L type parts by forging process is used to understand the microstructure change and mechanical properties of L type parts. Through the study of semi solid isothermal treatment and die forging of Mg-Gd magnesium alloy, the optimum preparation parameters of semi-solid billet of Mg-Gd magnesium alloy are determined. It is confirmed that the forming process method of die forging is used to determine the processing way of Mg-Gd magnesium alloy parts with simple process, low cost and high thermal physical properties of materials, and the semi-solid die forging is promoted. The application of technology in the forming technology of Mg-gd magnesium alloy. Semi solid isothermal treatment experiment. First, the semi-solid temperature range of the material was tested by DSC, and different temperatures were selected in the temperature range of the solid liquid phase. Then the isothermal treatment was carried out at different heat preservation time, and the materials were studied by means of scanning electron microscope and image analysis software. The evolution law of semisolid tissue is finally analyzed. The results show that the semi solid structure with fine grain, good spheroidization and uniform grain size can be obtained through semi solid isothermal treatment. The mechanical behavior of the material under isothermal compression in semisolid solid state is studied by semi solid isothermal compression experiments. It is found that Mg-Gd magnesium alloy is in semi solid state. The deformation resistance is low, the coordination ability in the deformation process is good, and the Mg-Gd magnesium alloy under semi-solid state has the sensitivity of deformation temperature and strain rate. Finally, through the production process experiment, the forging process is adopted, and the L type parts are used as the concrete parts, the L type parts are successfully manufactured on the pressure machine. The mechanical properties and the mechanical properties are tested. The microstructures were observed and analyzed.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG319
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本文编号：1952667