Ambient-temperature creep failure of silver-aided diffusion bonds between steel
It has long been known that thin (e.g., 1 {mu}m {minus} 1 mm) interlayer bonds between higher strength base materials may have high ultimate tensile or rupture strengths despite the relatively low strength of the filler metal. The high strength of the joint is due to the mechanical constraint provided by the stronger base metals which restricts transverse contraction of the interlayer. The constraint produces a triaxial state or stress and reduces the effective stress, thus reducing the tendency for the interlayer to plastically deform. Plasticity of the base metal reduces the constraint and decreases the strength of the bond. The purpose of this work was twofold. First, the validity of the base-metal- accelerated'' delayed-failure theory for bonds utilizing plastic base metals was checked. Creep-rupture tests were performed on diffusion-bonded specimens using silver interlayers deposited by planar-magnetron sputtering (PMS), a physical vapor-deposition process. The PMS process was preferred because of the superior quality and strength of the bond and because this modern low-temperature joining process is increasingly utilized for joining ceramic and composite materials. The role of plastic base metals in the fracture process was further investigated by conducting tensile-rupture tests of diffusion bonds made with stainless steel base metals of different yield strengths, and therefore different creep rates. The second purpose was to determine whether delayed failure occurs in interlayer bonds between elastic base metals, which do not creep over the range of applied stresses. This question is particularly relevant since many alloys, ceramics and composites fall within this category. Again, ambient and near-ambient temperature creep-rupture tests were performed at a variety of stresses below the UTS of the bond. 25 refs., 7 figs.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- DOE/DP
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 6978879
- Report Number(s):
- UCRL-101690; CONF-9003155-1; ON: DE90010687
- Resource Relation:
- Conference: 2. international conference on diffusion bonding-applications, Cranfield (UK), 28-29 Mar 1990
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
MARAGING STEELS
DIFFUSION WELDING
SILVER
STAINLESS STEEL-304
WELDED JOINTS
CREEP
FAILURES
PLASTICITY
TENSILE PROPERTIES
ALLOYS
AUSTENITIC STEELS
CHROMIUM ALLOYS
CHROMIUM-NICKEL STEELS
CORROSION RESISTANT ALLOYS
ELEMENTS
FABRICATION
HEAT RESISTANT MATERIALS
HEAT RESISTING ALLOYS
HIGH ALLOY STEELS
IRON ALLOYS
IRON BASE ALLOYS
JOINING
JOINTS
MARTENSITIC STEELS
MATERIALS
MECHANICAL PROPERTIES
METALS
NICKEL ALLOYS
STAINLESS STEELS
STEEL-CR19NI10
STEELS
TRANSITION ELEMENTS
WELDING
360103* - Metals & Alloys- Mechanical Properties
360101 - Metals & Alloys- Preparation & Fabrication