N.S.Stoloff Department of Materials Engineering
,
Rensselaer Polytechnic Institute
,
Troy
,
New York
,
USAC.T.Liu Metals and Ceramics Division
,
Oak Ridge National Laboratory
,
Oak Ridge
,
Tennessee
,
USA
材料科学技术（英文）
A comprehensive review of low temperature environmental embrittlement in intermetallics is pres- ented. Moisture and hydrogen are shown to severely embrittle many intermetallics, including iron, nickel and titanium aluminides. The roles of composition, microstructure and external test variables are emphasized. Several methods to reduce or avoid embrittlement are described.
关键词:
environmental embrittlement
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null
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null
C. D. Lundin and C. Zhou (The University of Tennessee Knoxville
,
TN 37996
,
USA)
金属学报(英文版)
Accurate thermal simulation is the key in the simulation approach to defining the unique microstructure and properties of the HAZ regions. Simulation enables an expansion of the volume of material char- acteristic of each H4Z region to a sufficient size for property determination.The combined influence of heat input,preheat temperature, plate thickness, and widing process on HAZ microstructure and properties relics on the accurate simulation of thermal cycles corresponding to different peak temperatures using an HAZ simulator like the Gleeble.Several computer programs have been developed to predict thermal excursions in various HAZ regions during welding. Some were developed based simply on the thermal propertics of a material;whereas, others were generated on the basis of actual experimental data.A suitable HAZ thermal simulation program must be ons that can authntically duplicate an ac- tual thermal cycle experienced during welding within reasonable limies. Therefore, the similarities and differences among the HAZ thermal cycles predicted by various methodologies should be fully under- stood. A total of sts thermal cycle prediction methodologies were compared in this evaluation. It was de- termined that some HAZ simulation programs have sever limitations due to the idealized assumptions considered in their development.According to the experieare at The University of Tennessee and the comparison results in this study, the HAZ thermal simulation programs; " HAZ Calculator" and F(s, d); are recommended for accurate HAZ thermal cycle duplication.
关键词:
welding
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null
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