钪对镁-铝-锌合金显微组织与力学性能的影响.pdfVIP

学兔兔 铸 造 Sep．2008 FOUNDRY VO1．57 NO．9 钪对镁一铝一锌合金显微组织与力学性能的影响 肖代红，黄伯云 (中南大学粉末冶金国家重点试验室，湖南长沙410083) 摘要：通过铸锭冶金及形变热处理工艺，制备了含0．3％Sc~Mg一11AI．1．2Zn(质量分数)合金。采用x射线衍射、金相 及扫描电镜观察与拉伸性能测试，研究微量钪在基体合金中的作用与存在形式。结果表明，基体合金中添加0．3％Sc后， 合金的晶粒明显得到细化，Mg 7Al ：相的形态与分布得到有效改善。合金的相组成主要由仅一Mg基体相、Mg。7A1 ：相及 MgAlSc相组成。同时，0．3％Sc~添加也提高了挤压态合金在室温与高温下抗拉强度，室温时的抗拉强度达到340MPa， 而伸长率超过了10％。 关键词：镁一铝．锌合金；钪；显微组织；力学性能 中图分类号：TG146．22 文献标识码：A 文章编号：1001—4977(2008)09—0946—04 Effect of Trace Scandium on Microstructure and Mechanical Properties of Mg·-AI-·Zn Alloy XIAO Dai—hong，HUANG Bai-yun (State Key Laboratory of Powder Metallurgy，Central South University， Changsha 4 1 0083，H u’nan，China) Abstract： Mg．AI—Zn alloys with trace scandium were prepared by ingot metallurgy and thermo．mechanicaI treatment．The effects of scandium addition on the microstructure and mechanicaI of the alloys have been investigated by using of X—ray diffraction，optical microscope， scanning electron microscopy and tensile testing．It has been shown that the alloy structure iS mainly composed of phase a—Mg，Mg17Al12 and MgAISc when 0．3％Sc was added．The 0．3％Sc addition improves the morphology and distribution of Mg17Af12 phases．Such improved microstructure iS accompanied by the improvement of mechanical properties of the extruded alloy at room temperature and high temperature．At this condition，the tensile strength and elongation of the alloy with 0．3％Sc are 340 MPa and above 1 0％at the room temperature． Key words：Mg．A1．Zn alloys；scandium；microstructure；mec