平行挤压方向Mg-Dy-Zn合金板材的显微组织和力学性能的研究 毕业论文.docx

PAGE  PAGE 55 LANZHOU UNIVERSITY OF TECHNOLOGY 毕业设计(论文) 题 目 平行挤压方向Mg-Dy-Zn合金板材的显微组织和力学性能的研究 学生姓名 学 号 专业班级 金属材料(3)班 指导教师 学 院 材料科学与工程学院 答辩日期 2013 06 16 摘要 本次实验通过模具和合金原料在200°C下预热，在隔绝水和空气的前提下进行熔炼，熔炼Mg-Dy-Zn合金成型并冷却后进行合金的挤压。通过与挤压方向平行的方向取样。得到样品后，利用光学仪器观察铸态Mg-Dy-Zn合金与平行挤压方Mg-Dy-Zn合金的金相组织。利用SEM扫描通过观察铸态Mg-Dy-Zn合金以及与平行挤压方向Mg-Dy-Zn合金的显微组织图片。利用XRD分析合金的力学性能以及温度对力学性能的影响及其原因。结果表明：得出铸态的Mg-Dy-Zn合金挤压后晶格发生了畸变，LPSO相更加紧密，并且分???更加广泛有规律性，使材料获得更大的应变，挤压态的Mg-Dy-Zn合金挤压力学性能好于铸态Mg-Dy-Zn合金。挤压态的Mg-Dy-Zn合金抗拉压性能要高于铸态的Mg-Dy-Zn合金。且随着温度的增高，挤压态合金的最大应力变小，从而得出挤压态合金的力学性能随着温度的升高而下降。 关键词：Mg-Dy-Zn合金，力学性能，LPSO相。 ABSTRACT The experiment and the alloy material in a mold at 200 ° C preheated smelting isolated in the context of water and air, melting the alloy Mg-Dy-Zn alloy extrusion molding and cooling. With the direction parallel to the extrusion direction of the sample. Obtained after the sample was observed using an optical instrument-cast Mg-Dy-Zn alloy extrusion microstructure parallel side Mg-Dy-Zn alloy. Scan through the use of SEM observation of cast Mg-Dy-Zn alloy microstructure and parallel to the extrusion direction pictures and Mg-Dy-Zn alloy. XRD analysis of the use of the mechanical properties of the alloy and the temperature on the mechanical properties of their causes. The results showed that: after Mg-Dy-Zn alloy extrusion cast drawn lattice distortion, LPSO phase more closely and more widely distributed regularity, and the material greater strain, squeezing state Mg -Dy-Zn alloy extrusion mechanical properties better than cast Mg-Dy-Zn alloys. Tensile extruded alloy pressure performance Mg-Dy-Zn than Mg-Dy-Zn alloy as cast. And as the temperature increased, the maximum stress extruded alloy becomes smaller, so as to arrive mechanical properties of extruded alloy decreases with increasing temperature. Keywords: parallel to the extrusion direction Mg-Dy-Zn alloy, mechanical properties, LPSO phase. 目录  T