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通过拉伸试验机、腐蚀试验箱、DSC以及TEM等手段对淬火后预拉伸处理并自然时效至稳定状态的铝锂合金薄板的拉伸性能、腐蚀性能、时效响应特征以及微观组织进行了研究.结果表明,在0~6%范围内,合金的屈服强度随预拉伸量的增加而逐渐提高;预拉伸量低于3%时,合金的抗拉强度随拉伸量增加逐渐降低,在3%~6%范围内,抗拉强度趋于平稳;随预拉伸量增加,合金由明显的晶间腐蚀转为点蚀,T34状态点蚀深度最小,约为0.03 mm;预拉伸改变了合金的时效响应特征,使合金在100℃附近的吸热峰向高温移动,180℃及260℃附近的放热峰向低温区移动.淬火后的预拉伸在增加晶内位错密度的同时,抑制了d’相在晶内和晶界的析出,预拉伸量越大,晶内及晶界d’相的数量越少.位错及析出相的共同作用影响了合金的拉伸及腐蚀性能.
Tensile properties, corrosion properties, aging response characteristics and microstructure of Al-Li alloy sheets pretreated by quenching and natural aging to a steady state were studied by means of tensile testing machine, corrosion chamber, DSC and TEM. The results show that the yield strength of the alloy gradually increases with the increase of the pretensioning amount in the range of 0-6%. When the pretensioning amount is less than 3%, the tensile strength of the alloy decreases with the increase of the drawing amount, In the range of 3% ~ 6%, the tensile strength tends to be stable. With the increase of pre-stretch, the alloy changes from obvious intergranular corrosion to pitting corrosion, the pitting depth is the smallest at T34, about 0.03 mm. Which changed the aging response of the alloy and shifted the endothermic peak near 100 ℃ to high temperature and the exothermic peak near 180 ℃ and 260 ℃ moved to the low temperature.The pre-tensile quenching increased the intragranular dislocation density , While inhibiting the precipitation of d ’phase in the grain and grain boundaries, the greater the amount of pre-stretch, the smaller the number of d’ phase in the grain and grain boundaries The combination of dislocation and precipitated phase affects the pull of the alloy Extend and corrosion performance.