A critical review of aluminum welding was made to determine the kinds of internal defects which lower the strength and reliability of welds. The principal kinds of defects were found to be porosity and metallurgical changes in the heat affected zone.
Basic investigations have isolated single parameters and combinations of parameters which have statistical significance as causes of porosity. Improper time-temperature cycles are the cause of detrimental metallurgical changes.
Knowledge of the parameters, combinations of parameters, and time-temperature cycles can be used to produce significant improvement in the reliability of aluminum weldments