Destructive mechanism solution of aluminum secondary ingot 2019-01-1101
Aluminum is used to realize weight savings in automotive parts, and its use can be expected to increase in future. Honda is striving to realize a society with zero environmental impact, and in order to address climate change and energy issues and realize the efficient utilization of resources, has advanced a “Triple ZERO approach” which will see the company reducing CO2 emissions to zero using renewable energy, reducing energy risks to zero, and reducing resource and disposal risk to zero. As part of these efforts it would be desirable when employing aluminum to expand the use of secondary ingots, which reduces energy consumption during manufacture and realizes a considerable reduction in CO2 emissions. However, products manufactured using secondary ingots display issues with respect to mechanical properties and corrosion resistance, and the use of the ingots in actual products is therefore limited. The fact that secondary ingots contain a large volume of impurities in comparison to primary ingots promotes the generation of intermetallic compounds, causing the mechanical properties of cast products to deteriorate. Conventionally, the effect of intermetallic compounds on mechanical properties has been estimated from two-dimensional structure and fracture faces. The research discussed here evaluated intermetallic compounds in aluminum cast products from three-dimensions using high-resolution CT. In addition, fracture behavior was observed in situ, and the fracture mechanism was analyzed, making it possible to elucidate the actual means by which the shape of intermetallic compounds affect the mechanical properties of aluminum, and effect of parts strength was investigated at the time of using secondary ingot.