The Study On Heat-treatment Process And Performance Of2A97Alluminium-lithium Alloy

This article deals with the homogenization treatment of2A97aluminum-lithium alloy and the effect of aging process on the microstructure and mechanical properties of2A97alloy.Various testing methods were used, including Optical microscopy (OM),room-temperture tensile test, Scanning electron microscopy(SEM) and Transmission electron microscopy (TEM).The main conclusions are as following:(1) The homogenization treatment of this alloy is520℃/24h. and the overburnt temperature is530℃.(2) The main microstructure of this alloy aging at165℃is δ’,0’and T1phases. With the aging time extending, the number of T1increases significantly,becoming the dominant strengthening phase.The common strengthening effect of T1、θ’and δ’ phases is greater than the joint strengthening of δ’ and θ’,but the elongation declines.(3) Under the double-aging treatment (firstly pre-aging at low-temperature and then further aging at elevated temperature): Extending the pre-aging time has little effect on the strength of the alloy While when pre-aging time is fixed, the ultimate tensile strength and yield strength of the alloy increases by extending aging time, but the elongation decreases simultaneously.(4) By contrast, under the double-aging treatment (firstly pre-aging at high-temperature and then further aging at low-temperature):when the pre-aging time is24h, the strength of alloy improves with the final aging time extending. While when the pre-aging time is48h,extending the final aging time has tiny effect on the strength of this alloy(5) At the same aging temperrature,the anti-corrossion capacity of2A97alloy is:under aged> peak aged> over aged.While with the increase of aging temperature, the anti-corrosion capacity of alloy decrease.