Emerging trends in joining processes of Al-Li-X alloys

Diffusion bonding and super plastic deformation of 8090 alloy and its
composites in laminated variety have attractive industrial application. The competing
mechanisms behind acceptability of this process have centered the absence of key hole,
undercuts or surface non uniformities. The other processes described have been laser
beam welding (LBM), arc welding, electron beam melting and friction stir welding. The
dimensions have optimized to reproduce composition or processing consequences to
minimize free surface oxides and contaminations those inhibits diffusion bonding and
lower shear strength of joints with respect to base metal. Transient melting / diffusing
instances have stated to reproduce alloy and fabrication process design so as to remove
porosities and surface non uniformities. Requirement of vacuum and expensive production
have referred studies by laser beam welding (LBW) and electron beam welding (EBW)
techniques. Utilization of high energy density in case of LBW in N2 gas medium and
combined fully penetrated EBW combined with super plastic forming have showed the
encouraging results. Hot cracking susceptibility has studied to utilize advantages of light
weight and high specific modulus alloys. Selection of filler, weld penetration, gas shielding
and section thickness have been important criteria for prevention of hot cracking during
GTA or solidification.