7475アルミニウム合金板の大気中での超塑性成形•接合

抄録

Diffusion bonding of superplastic aluminum alloys has been generally carried out with insert materials or in vacuum, because the oxidized layer is too firm for diffusion bonding to take place. Diffusion bonding behavior of the superplastic 7475 aluminum alloy sheets was investigated without an insert material in air taking into account of the manufacturing process being easier by changing initial surface roughness, strain-rate, bonding pressure and time. Bonding was successfully performed at the thickness strain larger than 15%. Bonding strength proportionally increased with increasing thickness strain. The value of bonding strength was maximized by adjusting the strain rate during forming to that of superplastic condition (ε_??_1.1×10^-4s^-1) and with proper preparation of the initial surface roughness of the sheets. The maximum value obtained in this study was 40% of the original sheet.