Weldability and Grain Refinement of Al-2.2Li-2.7Cu.

摘要

The basic weldability of the alloy Aluminum-(2.2)Lithium -(2.7)Copper was investigated and compared with two common aluminum alloys: 2024 and 5083. The basic weldability was characterized by the susceptibility of the alloy to hot tearing as determined by the trans-varestraint test. The hot tearing susceptibility was characterized through plots of total crack length and maximum crack length versus augmented strain. These data were correlated with thermal profiles taken of the weld to provide additional characterization through the use of the brittle temperature range and critical strain rate for temperature drop parameters. The second part of the investigation explored the effect of grain refiner additions upon enhancing the weldability of the alloy. The grain refiners explored were titanium and zirconium, and their effects upon the weldability were determined by the Varestraint test. The results of the study showed the Al-(2.2)Li-(2.7)Cu alloy to have a high susceptibility to hot tearing. Additions of titanium and zirconium were found to enhance weldability through refinement of the grain structure and alteration of the shape and distribution of the eutectic phase in the weld. Reprints. (aw)