刘守法,周兆锋,刘丹成.Si添加对快速凝固/粉末冶金镁合金组织及力学性能的影响[J].有色金属工程,2019,9(9):.
Si添加对快速凝固/粉末冶金镁合金组织及力学性能的影响
Effect of Si Addition on Microstructure and Mechanical Properties of Mg-Al-Zn-Mn Alloy Fabricated by Rapidly solidified powder metallurgy
投稿时间:2018-12-06  修订日期:2019-01-31
DOI:
中文关键词:  快速凝固/粉末冶金  显微组织  力学性能  Mg2Si相  反向挤压
英文关键词:rapidly solidified powder metallurgy  microstructure  mechanical properties  Mg2Si phase  reverse extrusion
基金项目:国家科技重大专项(2017ZX04011-010); 陕西省教育厅专项科研计划项目(15JK2172)
        
作者单位
刘守法 西京学院 机械工程学院
周兆锋 南京航空航天大学 机电学院
刘丹成 西安航天发动机有限公司
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中文摘要:
      采用快速凝固/粉末冶金工艺分别制备Mg-8Al-0.5Zn-0.15Mn及Mg-8Al-0.5Zn-0.15Mn-2Si合金挤压棒材。利用光学显微镜、扫描电镜、透射电镜、X射线衍射仪及拉伸机,研究Si添加对Mg-Al-Zn-Mn合金显微组织及室温力学性能的影响。研究表明:与热压Mg-Al-Zn-Mn合金相比,热压Mg-Al-Zn-Mn-Si合金内晶界上网状分布的Mg17Al12相减少,晶内出现多边形状Mg2Si相。热压后的反向挤压过程中两种合金组织均发生连续动态再结晶,Mg-Al-Zn-Mn-Si晶粒细化较好,伸长率较大,第二相Mg2Si与基体接合良好。Mg2Si相周围容易出现应力集中,受拉伸作用时成为裂纹起始点,导致拉伸断裂模式为沿晶断裂,因为屈服强度和抗拉强度较小。随着反向挤压温度上升,两种合金屈服强度和抗拉强度均降低,而伸长率增大。
英文摘要:
      Mg-8Al-0.5Zn-0.15Mn and Mg-8Al-0.5Zn-0.15Mn-2Si extruded bars were prepared by Rapidly solidified powder metallurgy process. The effects of Si addition on the microstructure and mechanical properties of Mg-Al-Zn-Mn alloy were investigated by optical microscopy, scanning electron microscopy, transmission electron microscopy, X-ray diffractometry and stretching machine. The results show that compared with the hot-pressed Mg-Al-Zn-Mn alloy, the Mg17Al12 phase in the grain boundary of the hot-pressed Mg-Al-Zn-Mn-Si alloy decreases, and the polygonal Mg2Si phase appears in the crystal. During the reverse extrusion process, the two hot-pressed alloys undergo continuous dynamic recrystallization. Mg-Al-Zn-Mn-Si has fine crystal grains and large elongation, and the second phase Mg2Si is well bonded to the matrix. Stress concentration is likely to occur around the Mg2Si during stretching, which becomes the starting point of the crack, thereby lowering the yield strength and tensile strength. As the reverse extrusion temperature rises, both the yield strength and the tensile strength of the two alloys decrease, while the elongation increases.
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