Effect of Annealing on the Microstructure and Properties of Electron Beam Welded 4J34 Kovar Alloy

Journal Article · Sat Dec 15 04:00:00 EST 2018 · Journal of Materials Engineering and Performance

DOI:https://doi.org/10.1007/S11665-018-3757-0· OSTI ID:22971064

Chen, Guoqing; Zhang, Ge; Shu, Xi; Zhang, Binggang; Li, Jian; Feng, Jicai ^[1]

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1. Harbin Institute of Technology (China)

Electron beam welding of 4J34 Kovar alloy was conducted, and the microstructure and mechanical properties of the joints in as-welded and postweld annealing treatment (PWAT) states were investigated. The martensitic transformation occurred and led to the generation of α lath martensite due to the rapid cooling in the as-welded condition. After annealing treatment, part of the α martensite transformed to γ austenite and subsequently developed the bulk γ phase and α/γ lamellar microstructures in the fusion zone (FZ) of the postwelded joint. Grains in the heat-affected zone (HAZ) clearly developed and penetrated into the FZ, causing the disappearance of the fusion line between the FZ and the HAZ. All the joints in both the as-welded and PWAT conditions exhibited ductile fracture. The maximum tensile strength of 505 MPa was obtained in the as-welded joint with the welding speed of 150 mm/min. The linear expansion coefficients of the joint and base metal decreased with the increase in temperature. However, the decreasing rate of PWAT joints was lower than that of the as-welded joints.

• OSTI ID: 22971064
• Journal Information: Journal of Materials Engineering and Performance, Journal Name: Journal of Materials Engineering and Performance Journal Issue: 12 Vol. 27; ISSN 1059-9495; ISSN JMEPEG
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ANNEALING
AUSTENITE
ELECTRON BEAM WELDING
ELECTRON BEAMS
HEAT AFFECTED ZONE
KOVAR
MARTENSITE
MICROSTRUCTURE
PHASE TRANSFORMATIONS
TENSILE PROPERTIES