US 7,575,811 B2
	Aluminum alloy sheet for superplastic forming
Hidetoshi Uchida, Tokyo (Japan); Yasunori Nagai, Tokyo (Japan); Takamichi Watanabe, Tokyo (Japan); Hitoshi Kazama, Wako (Japan); Osamu Yokoyama, Haga-machi (Japan); and Kazuya Saito, Haga-machi (Japan)
Assigned to Sumitomo Light Metal Industries, Ltd., Tokyo (Japan); and Honda Motor Co., Ltd., Tokyo (Japan)
Filed on Aug. 29, 2006, as Appl. No. 11/511,894.
Claims priority of application No. 2005-249662 (JP), filed on Aug. 30, 2005.
Prior Publication US 2007/0048539 A1, Mar. 01, 2007
Int. Cl. B32B 9/00 (2006.01)

U.S. Cl. 428—469  [428/472; 428/701; 428/702]

3 Claims

1. In an aluminum alloy sheet having a surface brought into contact with a die and subjected to superplastic forming in the die, the improvement comprising said surface of the aluminum alloy sheet having a two-layer film comprising a first film formed by etching the aluminum alloy sheet with an alkaline solution and a boehmite film formed on the first film and being in contact with the die.