Study on Solidification of Aluminum Alloy Weld Metal (Report 1)

Experiments on High Pure Al Thin Plate

Abstract

At present, it is very difficult to make clear solidification processing of weld metal, because it includes various problems which are difficult to solve theoretically and experimentally.
This experiments, as a fundamental stage to make clear the solidification processing, were performed on high pure Al, in which solidification processing is comparatively simple, by TIG arc spot welding, which needs no filler metal. Measurement of temperature was carefully carried out by very slender thermocouple, and also dynamic observation of sloid-liquid interface in whole solidification processing was performed by high speed camera.
The experimental results were analized from the following points such as behavior of solid-liquid interface, solidification rate, temperature distribution, cooling rate, temperature gradient, undercooling, and the relation between points mentioned above and welding conditions.
As the analized results, it was found that the transitional measurements were considerably different from calculated values based on theory of heat conduction, because it was based on mean value in solidification processing.