Mg-Nd-Y-Zr合金的无熔剂保护制备工艺研究

A Study on the Preparation of Mg-Nd-Y-Zr Alloy Under Non-flux Melting Protection

以金属镁、金属钕、镁钇中间合金和镁锆中间合金为原料,进行Mg-Nd-Y-Zr合金的无熔剂制备工艺的研究。通过考察熔炼温度、熔炼时间、合金液静置时间以及浇铸温度等工艺参数对合金收率、合金元素收率以及合金元素偏析程度等技术指标的影响,结合对合金铸态组织结构的研究,确定Mg-Nd-Y-Zr合金的均质纯净化制备工艺条件为:熔炼温度770℃、熔炼时间150 min、物料加入速率50 g/min、保护气中SF6体积分数0.1%、合金液静置时间60 min以及浇铸温度740℃。该工艺条件下,合金收率大于96%,合金元素偏析程度为±(0.05~0.15)%(质量分数),合金元素含量偏差±(0.03~0.10)%(质量分数),合金内部无氧化缺陷,无杂质元素的引入富集。合金中的典型强化相为Mg41Nd5、Mg12Nd及Mg2Y相,呈网状分布,钕和钇元素对合金具有弥散强化作用;锆元素在合金中具有晶粒细化和铁杂质去除的双重作用。

The preparation of Mg-Nd-Y-Zr alloy by non-flux melting process of magnesium,neodymium,Mg-25Y master alloy and Mg-25Zr master alloy was investigated.The research based on effect of melting temperature,melting time,stewing time and casting temperature on yield of alloy,elements,etc.was studied which combined with as-cast microstructure analysis of alloy.The results show that the optimal conditions are melting temperature 770-780℃,melting time 150 min,charging rate of raw materials 50 g/min,concentration of SF 6 0.1vol%,stewing time 60 min and casting temperature 740℃.The yield of alloy is greater than 96%;the segregation degree of alloying elements is±(0.05-0.15)wt%and content deviation of alloying elements is±(0.03-0.10)wt%.There are no oxidation defects and no enrichment of impurity elements.The typical strengthening phases are Mg 41 Nd 5,Mg 12 Nd and Mg 2Y and network-like distribution;neodymium and yttrium have dispersion strengthening function to alloy;zirconium have gain refinement and ferrum removal effects to magnesium alloy.