激光合成Ni65Al35掺杂钨精矿粉合金组织及性能研究

选用亚共晶Ni65Al35粉末,加入不同含量的钨精矿粉并压制成坯。利用激光引燃自蔓延烧结合成技术合成NiAl基复合材料。采用OM、XRD进行微观组织观察及结构分析,并进行硬度、耐磨性和耐蚀性能测试。结果表明:合成产物组织由针状晶和胞状晶组成;随钨精矿粉含量的增加,针状晶变得细小并逐渐转变为胞状晶;烧结合金产物物相由NiAl、Ni3Al、Ni4.22Al0.9、Ni17W3、Ni4W、Al2O3等组成。当钨精矿粉的质量分数为2%,合金硬度最高为654.7HK;耐磨性能最好,磨损率最低为0.31 mg/mm2;钨精矿粉的加入降低了烧结合金的耐蚀性能,减小了合金钝化区,钝化电位区间由1 500 mV缩短至1 100 mV。

Microstructure and properties of Ni65Al35 composite material blended with tungsten concentrate powder by laser synthesis

With hypoeutectic Ni65Al35 powder,and addition of different content of tungsten concentrate powder,the blank was pressed.NiAl matrix composites were synthesized by laser ignition induced SHS sintering technology.By means of OM and XRD,microstructure and structure of the sintered alloy were analyzed,and the hardness test and abrasion test were carried out.The experimental results show that the synthesized product consists of acicular crystal and columnar crystal.With the increase of the content of tungsten concentrate powder,acicular crystal becomes small and gradually transforms into cellular crystal;the product phases of the sintered alloy are NiAl,Ni3Al,Ni4.22Al0.9,Ni17W3,Ni4W,Al2O3.When adding 2% tungsten concentrate powder,the micro hardness of the sintered alloy is the highest,which is 654.7HK;the wear rate of the sintered alloy is the lowest,which is 0.31 mg/mm2;with the addition of tungsten concentrate powder,alloy passivation is reduced.Passivation range shortens from 1 500 mv to 1 100 mv.