硬质相对冷喷涂FeAl金属间化合物涂层性能的影响

FeAl金属间化合物具有优良的物理性能和力学性能,但其室温塑性和断裂韧性低,限制了其工程应用.利用机械合金化制备了Fe(Al)固溶体合金粉末及Al2O3,WC硬质相增强的复合合金粉末,通过冷喷涂沉积涂层并结合后热处理原位反应制备了FeAl金属间化合物涂层及其复合涂层.利用扫描电镜(SEM)、X射线衍射仪(XRD)及显微硬度仪等研究了硬质相对球磨粉末组织结构、冷喷涂FeAl金属间化合物涂层组织结构及性能的影响.结果表明.硬质相可显著加速球磨粉末内部层状结构的细化程度,喷涂态涂层具有不同于传统热喷涂涂层的层状组织结构,热处理可实现喷涂态涂层中Fe(Al)固溶体向FeAl金属间化合物的原位转变,致使层状结构消失,获得无粒子界面的FeAl金属间化合物涂层,弥散分布的硬质相可显著提高冷喷涂FeAl金属间化合物涂层的强化稳定性.

Influence of Hard Phase on the Properties of Cold-Sprayed FeAl Intermetallic Compound Coatings

FeAl intermetallic compounds had excellent physical and mechanical properties. However, their industrial applications were limited by low room temperature ductility and fracture toughness. Thus FeAl intermetallic compound coating and the same coatings reinforced with hard phases Al2 O3 and WC were in-situ prepared by cold spraying of mechanically alloyed Fe(Al) solid solution alloy powder, Fe(Al)/Al2O3 and Fe( Al)/WC composite powder and follow-up post- spraying heat treatment. The influence of hard phases Al2 O3 and WC on the microstructure, phase composition and microhardness of cold - sprayed FeAl - based composite coatings was investigated by means of scanning electron microscopy, X- ray diffraction and microhardness testing. Resuhs show that the hard phases can accelerate the microstructure refinement of ball - milled powder. The as - sprayed coatings exhibited the same composition and structure as those of ball - milled materials for spraying. Moreover, heat treatment resulted in the complete transformation from Fe ( Al) solid solution to FeAl intermetallic compound and enhanced interfacial bonding of deposited particles. The dispersed hard phases could significantly increase the microhardness of the cold - sprayed FeAl intermetallic compound coatings.