Welding and weldability of nickel-iron aluminides

Journal Article · Tue Jan 01 00:00:00 EST 1985 · Weld. J. (Miami); (United States)

OSTI ID:5112850

David, S A; Horton, J A; Jemian, W A; Liu, C T

An important area in the development of any commercial alloy is the ease with which it may be joined or welded. A study was undertaken to investigate the weldability of the borondoped (500 ppm by weight) ductile aluminides by gas tungsten arc (GTA) and electron beam (EB) welding processes. Autogenous GTA welding of boroncontaining nickel-iron aluminides produced severe cracking within the weld metal and the heat-affected zone (HAZ). The hot cracking appears to be related to complex phase changes that the material undergoes at elevated temperatures in the HAZ and also during the liquid-tosolid transformation in the fusion zone. A series of EB welds with welding speeds ranging from 13 to 64 mm/s (30 to 150 ipm) with varying beam focus conditions gave successful complete joint penetration welds only in a narrow range of speeds and focus conditions. The cracks were predominantly intergranular in the HAZ and interdendritic in the fusion zone presumably associated with the presence of NiAl (..beta..') phase along the grain boundaries and interdendritic regions. Transmission electron microscopy (TEM) revealed tetragonal distortions of the ordered B2 (NiAl type) phase with a martensitic appearance. Microprobe analysis revealed extensive solute redistribution in the fusion zone and the HAZ as a result of the weld thermal cycle.

• Research Organization: Oak Ridge Nat. Lab, Oak Ridge, TN
• OSTI ID: 5112850
• Journal Information: Weld. J. (Miami); (United States), Vol. 64:1
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM COMPOUNDS
ELECTRON BEAM WELDING
GAS TUNGSTEN-ARC WELDING
WELDABILITY
IRON COMPOUNDS
NICKEL COMPOUNDS
WELDED JOINTS
FRACTURES
BORON COMPOUNDS
CRACKS
CRYSTAL DOPING
DOPED MATERIALS
MICROSTRUCTURE
TEMPERATURE EFFECTS
TETRAGONAL LATTICES
THERMODYNAMIC PROPERTIES
TRANSMISSION ELECTRON MICROSCOPY
ARC WELDING
CRYSTAL LATTICES
CRYSTAL STRUCTURE
ELECTRON MICROSCOPY
FABRICATION
FAILURES
JOINING
JOINTS
MATERIALS
MICROSCOPY
PHYSICAL PROPERTIES
TRANSITION ELEMENT COMPOUNDS
WELDING
360101* - Metals & Alloys- Preparation & Fabrication