Correlation of Neutron-Based Strain Imaging and Mechanical Behavior of Armor Steel Welds Produced with the Hybrid Laser Arc Welding Process.

Bragg edge neutron transmission imaging was used to characterize the spatial distribution of thermally induced residual strains in a steel armor plate welded with a hybrid laser arc process. This residual strain distribution was compared to the spatial development of mechanical strain during uniaxial deformation. By correlating the strain measurements of both methods, the failure mechanism was determined in armor welds joined with this process. Weld failure consistently occurred in the subcritical heat-affected zone where mechanical strain accumulation in softened martensitic parent material was superimposed upon the weld region containing the highest residual thermally induced strain.