Abstract: The prestrain and prestress around the interference – fit hole for hard – aluminum alloy LY12CZ sheet under tension load, levels of 35%σ 0.2, 60%σ 0.2 and 68%σ 0.2, are studied by Moiye’s method. The study shows, under 3.1% interference level, the stability of prestress is worse when load equals or exceeds using limit (67%σ 0.2 loading level) of hard – aluminum alloy LY12CZ. It is adverse to prevent the emergence of fatigue crack.

Key words: Character, Interference – fit, Limit load, Prestress