摘要
Mechanical properties and microstructure changes have been investigated on anew nickel-base superalloy after long-term aging at 700 deg C. It is found that the majorprecipitates of the tested alloy are MC, M_(23)C_6, M_6C and y' in the course of long4erm aging at700 deg C. The carbides maintain good thermal stability with the aging time up to 5008 h. The growthrate of gamma prime precipitates is relatively high in the early aging period and then slows down.The coarsening behavior of gamma prime follows a diffusion-controlled growth procedure. The roomtemperature Rockwell hardness of the alloy aged at 700 deg C increases slightly at the initial stageof aging, but it decreases with the prolonged time. It mainly depends on the size of gamma prime.In comparison with Nimonic alloy 263, the new alloy characterizes with higher tensile andstress-rupture strengths at high temperatures. The new nickel-base superalloy offers a combinationof microstructure stability, strength, ductility and toughness at 700 deg C.
Mechanical properties and microstructure changes have been investigated on anew nickel-base superalloy after long-term aging at 700 deg C. It is found that the majorprecipitates of the tested alloy are MC, M_(23)C_6, M_6C and y' in the course of long4erm aging at700 deg C. The carbides maintain good thermal stability with the aging time up to 5008 h. The growthrate of gamma prime precipitates is relatively high in the early aging period and then slows down.The coarsening behavior of gamma prime follows a diffusion-controlled growth procedure. The roomtemperature Rockwell hardness of the alloy aged at 700 deg C increases slightly at the initial stageof aging, but it decreases with the prolonged time. It mainly depends on the size of gamma prime.In comparison with Nimonic alloy 263, the new alloy characterizes with higher tensile andstress-rupture strengths at high temperatures. The new nickel-base superalloy offers a combinationof microstructure stability, strength, ductility and toughness at 700 deg C.
