Thermo-mechanical treatment using resistance heating for production of fine grained heat-treatable aluminum alloy sheets

A new thermo-mechanical treatment using resistance heating is devised to produce fine grained aluminum alloy sheets. To examine the effectiveness of the treatment, simulating experiments are conducted using a heat-treatable 6061 aluminum alloy, and the grain size, hardness property, and tensile properties are measured and compared with those of the conventionally heat-treated sheets. The results are summarized as follows: (1) resistance heating at a current density of about 100 A mm−2 realizes heating the aluminum alloy sheet into the solution temperature range in 2 s, (2) complete achievement of rapid solution treatment by the resistance heating requires the condition that the precipitates exist finely in the matrix, (3) the new treatment decreases the grain size by approximately one-half but the mechanical properties are not remarkably improved.