U.S. Department of EnergyOffice of Scientific and Technical Information
Time-dependent failure of silver interlayer welds
Abstract
Silver interlayer diffusion welds exhibit very high tensile strengths, despite the soft interlayer, because of the constraint provided by the stronger base metals. However, despite the high tensile strength, diffusion-welded-silver joints undergo time-dependent failure, or creep rupture at relatively low tensile stresses at ambient temperature, apparently by a ductile microvoid-coalescence mechanism at the coated and welded interfaces. Two classes of time-dependent tensile failure were investigated. In the first case, the applied stress does not produce any plastic deformation in the base metal, and rupture appears to be controlled by time-dependent plasticity within the silver interlayer as a result of the effective stress in the interlayer. The plasticity causes cavity nucleation and, eventually, coalescence and rupture. In the second case, time-dependent plasticity is observed in the base metals, and concomitant shear occurs within the soft silver interlayer under a high triaxial stress state. Here, the time-dependent plasticity of the base metal accelerates rupture. These models were substantiated by analyses of the stress and temperature dependence of the rupture times, finite-element analysis of the stress state within the interlayer, and microscopy of the fracture surfaces and interfaces loaded to various fractions of the expected rupture times. The procedures for preparing silver interlayersmore »
- Authors:
- Publication Date:
- Research Org.:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Org.:
- DOE/DP
- OSTI Identifier:
- 6990167
- Report Number(s):
- UCRL-53945
ON: DE90008015
- DOE Contract Number:
- W-7405-ENG-48
- Resource Type:
- Technical Report
- Resource Relation:
- Other Information: Thesis (Ph.D.)
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 36 MATERIALS SCIENCE; ALUMINIUM BASE ALLOYS; DIFFUSION WELDING; DEPLETED URANIUM; STAINLESS STEEL-304; WELDED JOINTS; FAILURES; ANNEALING; COATINGS; CREEP; FINITE ELEMENT METHOD; HARDNESS; MICROSTRUCTURE; PLASTICITY; RUPTURES; SILVER; TEMPERATURE DEPENDENCE; TENSILE PROPERTIES; THICKNESS; ACTINIDES; ALLOYS; ALUMINIUM ALLOYS; AUSTENITIC STEELS; CHROMIUM ALLOYS; CHROMIUM-NICKEL STEELS; CORROSION RESISTANT ALLOYS; CRYSTAL STRUCTURE; DIMENSIONS; ELEMENTS; FABRICATION; HEAT RESISTANT MATERIALS; HEAT RESISTING ALLOYS; HEAT TREATMENTS; HIGH ALLOY STEELS; IRON ALLOYS; IRON BASE ALLOYS; JOINING; JOINTS; MATERIALS; MECHANICAL PROPERTIES; METALS; NICKEL ALLOYS; NUMERICAL SOLUTION; STAINLESS STEELS; STEEL-CR19NI10; STEELS; TRANSITION ELEMENTS; URANIUM; WELDING; 360101* - Metals & Alloys- Preparation & Fabrication; 360103 - Metals & Alloys- Mechanical Properties; 360102 - Metals & Alloys- Structure & Phase Studies
Citation Formats
Rosen, R. S. Time-dependent failure of silver interlayer welds. United States: N. p., 1990.
Web. doi:10.2172/6990167.
Rosen, R. S. Time-dependent failure of silver interlayer welds. United States. https://doi.org/10.2172/6990167
Rosen, R. S. 1990.
"Time-dependent failure of silver interlayer welds". United States. https://doi.org/10.2172/6990167. https://www.osti.gov/servlets/purl/6990167.
@article{osti_6990167,
title = {Time-dependent failure of silver interlayer welds},
author = {Rosen, R. S.},
abstractNote = {Silver interlayer diffusion welds exhibit very high tensile strengths, despite the soft interlayer, because of the constraint provided by the stronger base metals. However, despite the high tensile strength, diffusion-welded-silver joints undergo time-dependent failure, or creep rupture at relatively low tensile stresses at ambient temperature, apparently by a ductile microvoid-coalescence mechanism at the coated and welded interfaces. Two classes of time-dependent tensile failure were investigated. In the first case, the applied stress does not produce any plastic deformation in the base metal, and rupture appears to be controlled by time-dependent plasticity within the silver interlayer as a result of the effective stress in the interlayer. The plasticity causes cavity nucleation and, eventually, coalescence and rupture. In the second case, time-dependent plasticity is observed in the base metals, and concomitant shear occurs within the soft silver interlayer under a high triaxial stress state. Here, the time-dependent plasticity of the base metal accelerates rupture. These models were substantiated by analyses of the stress and temperature dependence of the rupture times, finite-element analysis of the stress state within the interlayer, and microscopy of the fracture surfaces and interfaces loaded to various fractions of the expected rupture times. The procedures for preparing silver interlayers by planar-magnetron sputtering were developed in this research. This process was preferred over other interlayer fabrication methods, such as brazing, electrodeposition, and other physical vapor deposition processes, because of the more reproducible results obtained using planar-magnetron sputtering. The findings of this research, however, are applicable to joints in which the interlayers are prepared by these and other processes. 79 refs., 72 figs., 4 tabs.},
doi = {10.2172/6990167},
url = {https://www.osti.gov/biblio/6990167},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Thu Feb 01 00:00:00 EST 1990},
month = {Thu Feb 01 00:00:00 EST 1990}
}