Quasi-quantitative control of the properties at room temperature and 1000°C of NiAl-based composites prepared by hot press sintering

Abstract

For high-temperature structural materials such as NiAl, the selection of appropriate mechanical properties to meet the room-temperature ductility and high-temperature strength required for practical engineering applications is a pressing issue. To address this issue, novel NiAl-based composites reinforced by 3-dimensional network structure were prepared using pre-alloyed powders sieved into five different particle size ranges. All composites in this paper had excellent mechanical properties as the 3-dimensional network structure could improve both room-temperature ductility and high-temperature strength. Due to almost each powders grew into one grain during the hot pressing sintering process and the grains did not grew further caused by the hindrance of the 3-dimensional network structure, the particle size of the original powders and the grain size of the composites showed an obvious linear relationship. The relationship among original powder particle size, grain size and mechanical properties of the NiAl-based composites was established by fitting method, and the fitted equations were validated with an average deviation of 2.45%, so that quasi-quantitative control of the mechanical properties could be achieved by designing the original powder particle size. This work allowed both room and high temperature mechanical properties of NiAl to be improved and quasi-quantitative control over them, which provided a new idea for the design of composites.