In order to know the longest permissible thermal exposure time during which the cold worked (CW) microstructure would remain unchanged, the effect of the thermal exposure at temperatures ranging from 910?℃ to 1?070?...In order to know the longest permissible thermal exposure time during which the cold worked (CW) microstructure would remain unchanged, the effect of the thermal exposure at temperatures ranging from 910?℃ to 1?070?℃ on the microstructure was investigated for MP159 alloy by optical microscopy and transmission electron microscopy (TEM). Such a study can provide guidance for determining reasonable hot forging parameters of fasteners. The results indicate that the intersecting network of fine platelets in CW microstructure are thermal stable when thermal exposure temperature does not exceed 920?℃. When thermal exposure temperature exceed 920?℃, the intersecting network of fine platelets will dissolve, but the thermal exposure temperature has the longest permissible thermal exposure time during which the intersecting network of fine platelets will not dissolve.展开更多
The microstructural changes of both solution heat treated (ST) and cold worked (CW) MP159 alloy during aging were investigated by optical microscopy and transmission electron microscopy (TEM). The results indicate tha...The microstructural changes of both solution heat treated (ST) and cold worked (CW) MP159 alloy during aging were investigated by optical microscopy and transmission electron microscopy (TEM). The results indicate that both solution heat treated (ST) and cold worked (CW) MP159 alloy could be hardened by aging. This aging induced hardening is attributable to the precipitation of a very finely dispersed ordered cubic γ′ phase particles with only several nanometres in diameter. The hexagonal close packed (HCP) ε martensite precipitated during aging of both CW MP159 and CW MP35N, and the hexagonal ordered Co 3Mo phase of the DO 19 structure type precipitated during aging of CW MP35N, have not been found in the present investigation.展开更多
文摘In order to know the longest permissible thermal exposure time during which the cold worked (CW) microstructure would remain unchanged, the effect of the thermal exposure at temperatures ranging from 910?℃ to 1?070?℃ on the microstructure was investigated for MP159 alloy by optical microscopy and transmission electron microscopy (TEM). Such a study can provide guidance for determining reasonable hot forging parameters of fasteners. The results indicate that the intersecting network of fine platelets in CW microstructure are thermal stable when thermal exposure temperature does not exceed 920?℃. When thermal exposure temperature exceed 920?℃, the intersecting network of fine platelets will dissolve, but the thermal exposure temperature has the longest permissible thermal exposure time during which the intersecting network of fine platelets will not dissolve.
文摘The microstructural changes of both solution heat treated (ST) and cold worked (CW) MP159 alloy during aging were investigated by optical microscopy and transmission electron microscopy (TEM). The results indicate that both solution heat treated (ST) and cold worked (CW) MP159 alloy could be hardened by aging. This aging induced hardening is attributable to the precipitation of a very finely dispersed ordered cubic γ′ phase particles with only several nanometres in diameter. The hexagonal close packed (HCP) ε martensite precipitated during aging of both CW MP159 and CW MP35N, and the hexagonal ordered Co 3Mo phase of the DO 19 structure type precipitated during aging of CW MP35N, have not been found in the present investigation.