微量稀土La对细晶W-Ni-Fe合金显微组织和性能的影响  

Influence of trace La on microstructure and properties of fine-graind W-Ni-Fe alloys

作　　者：曾毅[1] 范景莲[1] 李勇明[1] 刘涛[1] 田家敏[1] 

机构地区：[1]中南大学粉末冶金国家重点实验室,长沙410083

出　　处：《粉末冶金技术》2010年第6期403-406,共4页Powder Metallurgy Technology

基　　金：国家自然科学基金项目(50674106);国家自然科学基金创新群体项目(50721003);国家杰出青年科学基金项目(50925416)

摘　　要：采用喷雾干燥-热还原方法制备了纳米级93W-4.9Ni-2.1Fe复合粉末和添加了微量稀土La的复合粉末。研究了微量稀土La对合金性能和显微组织的影响。结果表明:微量稀土La的加入能够有效增加粉末的分散度;微量稀土La在合金中主要以中间相WxNixFexLax0x(摩尔比)的形式分布于粘结相中,该中间相在细化晶粒的同时对杂质元素Ca具有较好的亲和力,使合金性能得以提升。但随着过量La的增加,其生成的中间相容易在钨晶界和钨与粘结相的相界面上产生偏聚,降低了合金的界面结合强度,从而使合金性能降低。Nano-grained W-Ni-Fe composite powders and La doped W-Ni-Fe composite powders were fabricated by spray drying and subsequent thermal reduction process.The influence of trace La on the microstructure and properties of La doped W-Ni-Fe composite powders was investigated.The result shows that trace rare earth La addition can significantly increase the dispersity of the W-Ni-Fe composite powders.The addition of trace La forms an intermediate phase WxNixFexLaxOx in the bonding phase of fine-grain W-Ni-Fe alloys.This intermediate phase inhibits the growth of tungsten particle while it can absorbs the impurity Ca,which is responsible for increase of the tensile strength and elongation of the alloy.However,as the addition of the excessive rare earth La,the intermediate phase prefer to aggregate in the W-W interface and W-M interface,which decreases the bonding strength and induces the decrease of mechanical property.

关 键 词：微量稀土La 细晶W-Ni-Fe合金 显微组织 力学性能 

分 类 号：TG146.411[一般工业技术—材料科学与工程]