真空电磁悬浮精炼钛铝基中间合金试验研究

利用真空电磁悬浮熔炼炉对铝热法还原攀枝花酸溶性钛渣所得的粗TiAl基合金进行精炼,研究了精炼前后合金物相组成、合金元素在微区中的分布、组织结构和杂质含量的变化。发现在精炼参数为熔炼电流60A,保温时间5min,冷却速率4A/min时,精炼后的合金层片状组织和裂纹减少,晶粒尺寸减小。Si、Fe元素置换Al元素形成置换固溶相,存在于TiAl、TiAl_2等相中,形成了Fe_2AlTi、Si_2Ti、Al_2FeSi、AlFe、FeTiSi等物相,接近于Ti-Al二元合金的双相组织。合金中夹杂物的含量减少了45%,去除了合金中的粒径5μm的大颗粒夹杂物。

Experimental Study of Vacuum Electromagnetic Levitation Refining of TiAl Intermetallic Alloy

Refining of crude TiAl based alloy which was obtained through aluminothermic reduction of acid-soluble titanium slag in Panzhihua was carried out using vacuum electromagnetic levitation melting furnace.Phase composition,distribution of alloy elements in micro area,microstructure and impurities content of the alloy before and after refining were studied in present study.It is found that when the refining parameters of melting current,holding time and cooling rate were respectively 60 A,5 min and 4 A/main,the lamellar structures,amount of cracks and grain size of the alloy after refining decreased.Si and Fe presented in the phases of TiAl and TiAl2 etc.by substituting Al element to form substitutional solid solution phases,and eventually formed the phases of Fe2AlTi,Si2Ti,Al2FeSi,AlFe and FeTiSi etc.,close to the double phase structure of Ti-Al binary alloy.The inclusions content in the alloy reduced by 45％ and inclusions with size more than 5 μm were removed by refining.