Optimization of mechanical properties of cast NiAl-28Cr-5.5Mo-0.5Hf alloy
(1.辽宁省沈阳市科学院科学院金属研究所2.Department of Materials Engineering, Dalian University of Technology, Dalian 116024, China3.Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China4.中国科学院 金属研究所，沈阳 100016)
Abstract: The effects of different processing techniques on the microstructure and compressive properties of NiAl–28Cr-5.5Mo-0.5Hf alloys were evaluated. These processing routes can all improve the compressive properties of NiAl–28Cr-5.5Mo-0.5Hf alloys. The microstructural refinement and the stronger precipitation strengthening mechanisms are responsible to the improvement of the compressive properties under the condition of higher undercooling degree. In addition, high magnetic field treatment and trace rare earth elements addition can significantly optimize the mechanical properties of NiAl-28Cr-5.5Mo-0.5Hf alloy. The improvement of NiAl-28Cr-5.5Mo-0.5Hf alloy seems to be realized by a complicated combination of different processing route. A directional solidification at a high drawing rate under high magnetic field for NiAl-28Cr-5.5Mo-0.5Hf alloy containing minor rare earth element is a desirable route to the high performance NiAl-28Cr-5.5Mo-0.5Hf alloy.
Key words: NiAl-28Cr-5.5Mo-0.5Hf; processing; microstructure refinement; precipitation strengthening; high solidification rate