电磁搅拌对Al-5Ti-B中间合金组织及细化效果的影响  

Effect of Electromagnetic Stirring on the Microstructure and Refinement of Al-5Ti-B Master Alloy

作　　者：李润霞[1] 张文华[1] 张鹏[1] 张博通 陈建春 于宝义[1] 

机构地区：[1]沈阳工业大学辽宁省高校轻金属材料与工程重点实验室,辽宁沈阳110870 [2]湖南金联星特种材料股份有限公司,湖南岳阳414005

出　　处：《铸造》2016年第1期1-5,共5页Foundry

基　　金：国家自然科学基金(50971092);辽宁省自然科学基金(201202166);沈阳市科技创新专项(F14-231-1-23)

摘　　要：研究了电磁搅拌对Al-5Ti-B中间合金组织、成分及细化效果的影响,并在不同的温度下利用DSC对Al-5Ti-B中间合金及其细化后的纯铝的凝固和熔化过程进行了差热分析。分析了两组合金中Ti Al_3及Ti B_2的相变过程,并在此基础上提出可能的晶粒细化机理。结果表明:在浇注前对熔体施加电流为220 A的电磁搅拌10 min,可使熔体的洁净度大幅提升,并且使Al-5Ti-B中间合金的Ti B_2相均匀分布于Al基体上,在此工艺条件下制备的Al-5Ti-B中间合金可将纯铝晶粒细化至390μm左右。Al-5Ti-B中间合金以2℃/min凝固时发生了包晶反应;而Al-5Ti-B中间合金细化后的纯铝在相同温度下凝固时,没有发生包晶反应。合金熔体中的Ti浓度低于0.15%时,即使在平衡状态下凝固也不能发生包晶反应,即包晶反应由冷却速度和Ti浓度共同决定。The influence of electromagnetic stirring on the microstructure, ingredient and refinement of A1-5Ti-B master alloy was studied. The solidification and melting process of purity aluminum after refined by A1-5Ti-B master alloy and differential analysis of A/-5Ti-B master alloy was done at different heating and cooling rates by DSC. The phase transition of TiA13 and TiB2 was analyzed in the both alloys, and the possible mechanism of grain refining was put forward on this basis. The results indicate that cleanliness of melt is improved well after being electromagnetic stirred for ten minutes at 220 A electricity and TiB2 phase is dispersed in the Al-matrix. The grain of purity aluminum refined by the A1-5Ti-B master alloy is about 390 μm. A1-5Ti-B master alloy appeared peritectic reaction at 2 ℃/min cooling rate. But there is no peritectic reaction during solidification of purity aluminum after refined by A1-5Ti-B master alloy at the same rate. And there is not peritectic reaction in spite of cooling rate close to balance status when concentration of Ti can not reach 0.15%. That peritectic reaction is determined by the cooling rate and concentration of Ti.

关 键 词：电磁搅拌 细化机制 相变 包晶反应 

分 类 号：TG146.21[一般工业技术—材料科学与工程]