Microwave Module YAG Laser Weld Development

Technical Report · Sun Jun 30 20:00:00 EDT 1991

DOI:https://doi.org/10.2172/5409301· OSTI ID:5409301

Dereskiewicz, J. P. ^[1]

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1. Allied-Signal Aerospace Co., Kansas City, MO (United States)

Advance microwave products require low weld heat input, hermetically sealed, lightweight metal packages with low thermal coefficients of expansion and high thermal conductivity. Large quantities of these microwave packages are required. Use of the Nd:YAG laser with high silicon aluminum alloys is presently the best solution for the stated design criteria. Studies were conducted on seven aluminum-silicon (Al-Si) alloy combinations: 4047 Al to 1100 Al, 4047 Al to 6061-T6 Al, 4047 Al to 4047 Al, A40 to 1100 Al, A40 to 6061-T6 Al, A40 to 4047 Al, and A40 to A40. Weldability and leak rate were evaluated. A minimum leak rate of 10^-6 atm · cm³/s of He was desirable. Weld metal hot-cracking was the major factor limiting the ability to achieve the low He leak rate. Si content and weld metal ductility have the greatest influence on hot-cracking. Electron probe microanalysis (EMP) determined that a hermetic weld with leak rates of better than 10^-6 at · cm³/s of He could be obtained if silicon content in the weld metal was 7-26 weight percent silicon. Al-Si alloy combinations that would produce silicon contents in the desired range are 4047 to 4047, A40 to 1100, A40 to 6061-T6, and A40 to 4047. The recommended alloy combination is A40 to 1100 Al because the 1100 Al lid adds the most ductility to the weld metal when the preferred A40 housing is used. This added ductility absorbs more thermally induced stresses and reduces the likelihood of weld metal hot-cracking. Studies are planned to evaluate the effects of gold and nickel plating on weldability of Al-Si alloys. Other planned studies would evaluate temperature exposures around glass-to- metal connector seals during welding and the inclusion of purge tubes to the housing package for purge, backfill, and leak testing.

• Research Organization: Allied-Signal Aerospace Co., Kansas City, MO (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC04-76DP00613
• OSTI ID: 5409301
• Report Number(s): KCP--613-4385; ON: DE91015750
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360101* -- Metals & Alloys-- Preparation & Fabrication
42 ENGINEERING
420200 -- Engineering-- Facilities
Equipment
& Techniques
ALLOYS
ALUMINIUM ALLOYS
ALUMINIUM BASE ALLOYS
CRYSTAL STRUCTURE
DENSITY
ELECTRONIC EQUIPMENT
ELEMENTS
ELONGATION
EQUIPMENT
EXPANSION
FABRICATION
FLUIDS
GASES
HELIUM
JOINING
LASER WELDING
LASERS
LEAKS
MICROSCOPY
MICROSTRUCTURE
MICROWAVE EQUIPMENT
NEODYMIUM LASERS
NONMETALS
PHYSICAL PROPERTIES
POROSITY
RARE GASES
SILICON ALLOYS
SOLID STATE LASERS
THERMAL CONDUCTIVITY
THERMAL EXPANSION
THERMODYNAMIC PROPERTIES
WELDABILITY
WELDING