钇对AZ91镁合金晶粒大小显微组织及力学性能的影响.pdfVIP

学兔兔 Jan．2009 铸 造 VoI．58 NO．1 FOUNDRY · 53 · 钇对AZ91镁合金晶粒大小显微组织 及力学性能的影响 许春香，吕正玲 (太原理工大学材料科学与工程学院，山西太原030024) 摘要：采用光学显微镜、x射线衍射仪、扫描电镜等分析测试手段，研究了添加Y(0-3‰1．3％，质量分数)对AZ9I镁合 金晶粒大小、显微组织及力学性能的影响。结果表明，随Y添加量增加合金晶粒尺寸先由0．419mlTl增大到1．1l7InlTl后减 小到0．864mill，共晶组织先由网状分布变为离散岛状分布，随后又有聚集为断网状的趋势。当Y添加量为0．7％时，合 金共晶组织最细小，晶粒最大，Y与合金中Al反应生成块状新相Al2Y。向AZ91镁合金中添加少量Y后，常温下铸态合金 力学性能下降，高温 (200℃)下合金力学性能增强。 关键词：AZ91镁合金；钇；晶粒度；显微组织；力学性能 中图分类号：TG146．2 文献标识码：A 文章编号：1001—4977(2009)01—0053—04 Effect Of YttriUm On Grain Size．MicrostructUre and MechanicaI Properties of AZ91 Magnesium Alloy XU Chun—xiang．LU Zheng—ling (College of Material Science and Engineering，Taiyuan University and Technology， Taiyuan 030024，Shanxi，China) Abstract：The grain size。microstructure and mechanical properties of Az91-Y magnesium alloys have been studied using optical microscopy(OM)，X-ray diffraction(XRD)，scanning electron microscopy(SEM)，energy dispersive spectroscopy(EDS)and various testing machines，where is 0，0．3％，0_7％，1．0％and 1．3％ (by、^，f．)，respectively．Experimental results indicate that the grain size of oc-Mg matrix increases fr0m original 0．41 9 mm to1．1 1 7 mm and decreases to 0．864 mm while the morphology of 13-Mg1 I仃phase changes from continuous nets to discontinuous nets with an increase of yttrium concentration in magnesium alloys．When the Y addition reaches 0-7％．the finest discrete eutectic 13-Mg17AI17 is achieved with the largest grain size．a new phase AI2Y generates from the reaction between Y and AI in the melt．The ambient temperature tensile strength is decreased， but the elevated tempe