MICROSTRUCTURES AND PROPERTIES OF DZ40M Co-BASED SUPERALLOY AFTER LONG-TERM AGEING AT850℃
(1.Institute of Metal Research, Chinese Academy of Sciences,Shenyang110015, P. R. China
2.Department of Metal Meterials Engineering, ShenyangPolytechnic University,Shenyang110023, P. R. China)
2.Department of Metal Meterials Engineering, ShenyangPolytechnic University,Shenyang110023, P. R. China)
Abstract: DZ40M is a newly developed directionally solidified Co-based superalloy. Its microstructural characteristics and mechanical properties at room and elevated temperatures after ageing for 100~1 000 h at 850℃were studied. The results showed that 100h ageing at 850℃results in a substantial increase of tensile strength at room temperature and stress-rupture life at elevated temperatures, serious decrease of ductility at room temperature and improvement for stress-rupture ductility. With increasing ageing time, stress-rupture life tends to decrease and the other properties keep at essential constant. During ageing, primary carbides M7C3and MC decompose sluggishly, fine M23C6precipitates copiously around them and M6C forms on the sur-
face of some M7C3. The increased strength of the aged alloy is attributed to a strong interaction between M23C6and dislocations.
face of some M7C3. The increased strength of the aged alloy is attributed to a strong interaction between M23C6and dislocations.
Key words: directional solidification Co-based superalloy long-term ageing mechanical property