The effect of solid solution supersaturation on the precipitation of γ＇ in rapidly quenched Ni-AI binary alloys containing 11.6, 14.2 and 16.5 at. pct AI was investigated. The samples were solutioned at 1250℃, quen...The effect of solid solution supersaturation on the precipitation of γ＇ in rapidly quenched Ni-AI binary alloys containing 11.6, 14.2 and 16.5 at. pct AI was investigated. The samples were solutioned at 1250℃, quenched in iced brine, and then analyzed by electron microscopy and XRD （X-ray diffraction） techniques. In Ni-11.6 at. pct Al alloy, ordering and phase separation took place simultaneously, resulting in a uniform distribution of γ＇. A transition from uniform to bimodal γ＇ phase distribution occurred in the composition range between 14.2 and 16.5 at. pct Al. This transition was accompanied by changes in the morphology of γ＇ precipitates. The microstructural observations were discussed in view of both kinetics and crystallographic considerations.展开更多
An idealized tri-material assumption is established to describe the constitutive relationship of mismatched welded joints by considering the influence of heat affected zone（HAZ）.The fracture parameters Jand C＊are e...An idealized tri-material assumption is established to describe the constitutive relationship of mismatched welded joints by considering the influence of heat affected zone（HAZ）.The fracture parameters Jand C＊are estimated for mismatched welded joints with HAZ cracks by finite element analysis with ABAQUS.A middle crack tension（M（T））specimen is utilized in the analysis for different material properties and geometries of the weldment.The influence of mechanical property and geometry on the fracture parameters Jand C＊of the specimen is discussed for the welded joints with HAZ crack.The results suggest that the HAZ property is a significant factor in the estimation of Jand C＊for the mismatched welded joint with HAZ crack.展开更多
文摘The effect of solid solution supersaturation on the precipitation of γ＇ in rapidly quenched Ni-AI binary alloys containing 11.6, 14.2 and 16.5 at. pct AI was investigated. The samples were solutioned at 1250℃, quenched in iced brine, and then analyzed by electron microscopy and XRD （X-ray diffraction） techniques. In Ni-11.6 at. pct Al alloy, ordering and phase separation took place simultaneously, resulting in a uniform distribution of γ＇. A transition from uniform to bimodal γ＇ phase distribution occurred in the composition range between 14.2 and 16.5 at. pct Al. This transition was accompanied by changes in the morphology of γ＇ precipitates. The microstructural observations were discussed in view of both kinetics and crystallographic considerations.
基金Sponsored by National High Technology Research and Development Program of China(2012AA040106)
文摘An idealized tri-material assumption is established to describe the constitutive relationship of mismatched welded joints by considering the influence of heat affected zone（HAZ）.The fracture parameters Jand C＊are estimated for mismatched welded joints with HAZ cracks by finite element analysis with ABAQUS.A middle crack tension（M（T））specimen is utilized in the analysis for different material properties and geometries of the weldment.The influence of mechanical property and geometry on the fracture parameters Jand C＊of the specimen is discussed for the welded joints with HAZ crack.The results suggest that the HAZ property is a significant factor in the estimation of Jand C＊for the mismatched welded joint with HAZ crack.
