硼变质处理对Zn-50%Al合金铸态组织和力学性能的影响.pdfVIP

学兔兔 铸 造 Aug．2010 FOUNDRY VoI．59 NO．8 硼变质处理对Zn一50％Al合金铸态组织和 力学性能的影响 程巨强，刘志学 (西安工业大学材料与化工学院，陕西西安710032) 摘要：研究了硼变质处理及变质处理后保温时间对铸造Zn．50％A1合金组织和力学性能的影响。结果表明，Zn．50％A1 合金铸态枝晶发达，组织粗大，组织由初生Or．相、包围在 相外缘的a 共析组织组成。加入一定量的硼变质处理后， 可以细化铸造Zn-50％A1合金的组织，铸造组织由树枝状变为细小的等轴晶，硼加入量范围在0．04％-4)．08％，变质效果 较好，可以改善材料的力学性能。硼变质处理后随熔体保温时间的延长，存在变质衰退的现象，保温60 rnin以内浇注， 可保持较好细化效果。 关键词：硼；铸态Zn一50％A1合金；变质处理；组织；力学性能 中图分类号：TG146．1_1文献标识码：A 文章编号：1001—4977(2O{0)08—0838—03 E仟ects of Boron Modification on As—Cast Microstructure and Mechanical Properties of Zn-5O％AI Alloy CHENG Ju—qiang，LIU Zhi—xue (College of Materials Science and chemical Engineering，Xi’an Technological University， Xi。an 71 0032，Shaanxi，China) Abstract：Effects of boron modification and holding time after modification 0n as-cast microstructure and mechanicaI properties of Zn一50％Af alloy were studied．It iS found that as-cast microstructure of Zn．50％ alloy consists of coarse oc(AI)solid solution phase and oc+n eutectoid structure which distributes around the a(AI】phase．A certain amount of boron addition can refine the as-cast microstructure of Zn．50％AI alloy and change the microstructure of a phases from coarse dendrite into refined equiaxed crystal grain．The better refining effect can be obtained when the additionof boron jS fr0m 0．04％to 0．08％and the mechanicaI properties of Zn．5O％AI alloy can be jmproved．The modification effects of boron on the Zn一50％Al alloy fade with increasing of holding time．