Tensile properties of thin Au-Ni brazes between strong base materials
- Oregon State Univ., Corvallis, OR (United States)
It has long been known that when relatively strong base materials are joined by thin, soft, interlayer metals such as with brazing or various solid state joining processes, the ultimate tensile strength (UTS) of the bond may be several factors higher than the UTS of the bulk, or unconstrained, interlayer metals. However, earlier work reported by the authors confirmed that delayed or creep'' failure of the bond may occur at stresses much less than the UTS. It was found that for thin silver interlayers, prepared by brazing and physical vapor deposition (PVD), joining elastically deforming base materials (i.e. no measurable plastic deformation occurs in the base metal at the applied stresses), the ambient (and near-ambient) temperature time to failure is controlled by the creep rate of the silver interlayer which is determined by the effective stress within the interlayer. The plastic deformation within the interlayer causes cavity nucleation which continues until the concentration of nuclei is sufficiently high to lead to instability and eventual failure. The delayed failure may be accelerated by base material creep resulting from the effective stress in the base material. Plastic deformation in the base metal causes corresponding deformation in the interlayer, and cavities nucleate as with elastic base metal case. The delayed failure phenomenon was confirmed by the authors only for silver interlayers; other compositions were not tested. In this study, maraging steel was joined with an Au-Ni braze alloy with 57.5 at. % Au and 42.5 at. % Ni. The microstructure is expected to be a refined two-phase (spinodal) alloy with higher strength than the PVD silver of our previous investigation.
- Research Organization:
- Lawrence Livermore National Lab., CA (United States)
- Sponsoring Organization:
- USDOE; USDOE, Washington, DC (United States)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 5549035
- Report Number(s):
- UCRL-CR-109237; ON: DE92009677
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
BRAZED JOINTS
CREEP
GOLD BASE ALLOYS
TENSILE PROPERTIES
NICKEL ALLOYS
MARAGING STEELS
MICROSTRUCTURE
ULTIMATE STRENGTH
ALLOYS
CRYSTAL STRUCTURE
GOLD ALLOYS
IRON ALLOYS
IRON BASE ALLOYS
JOINTS
MARTENSITIC STEELS
MECHANICAL PROPERTIES
STEELS
WELDED JOINTS
360103* - Metals & Alloys- Mechanical Properties
360102 - Metals & Alloys- Structure & Phase Studies