【摘要】 采用X射线衍射、SEM、EDS等分析方法,研究了铁元素对光束堆焊合成NiAl金属间化合物层的成形和组织结构的影响规律。结果表明,光束堆焊镍铝混合粉制备NiAl金属间化合物层时,NiAl的高熔点导致堆焊层成形困难。在镍铝混合粉中加入适量铁粉(11at%～28at%)可以降低堆焊合金体系的熔点、改善堆焊层成形。随着铁粉加入量的增加,堆焊层的稀释率呈现先增加后降低的趋势,过多的铁粉加入量(43at%)将使熔池金属不能润湿母材。铁元素的引入使堆焊层中析出了Fe3Al相,随着堆焊层中含Fe量的增加,Fe3Al的析出量增加,堆焊层的微观组织为NiAl柱状晶和柱状晶间的Fe3Al条状相。更多还原

【Abstract】 With the use of X-ray diffraction, SEM and EDS, the effect of iron element on the formation of NiAl intermetallic light beam surfacing layer and its microstructure were investigated. The results show that owing to the high melting point of NiAl intermetallic, NiAl surfacing is difficult to acquire by light beam heating Ni and Al mixed powder. Adding reasonable content of Fe powder (11at%～28at%) to Ni and Al mixed powder can decrease the melting point of surfacing alloy system and improve the formation of light beam surfacing layer. With the increase of Fe addition in surfacing material, the dilution of surfacing layer and its Fe content firstly increase and then decrease. Too high addition of Fe powder (43at%) makes surfacing metal not to wet base metal. The Fe in surfacing layer promotes the precipitation of strip Fe3Al, and the precipitation proportion of strip Fe3Al increases with the increase of Fe content in surfacing layer. The light beam surfacing layer consists of NiAl column crystal and strip Fe3Al between column crystal.更多还原