新型高强韧铝锂合金的显微组织和性能

通过室温拉伸试验、热稳定化试验、扫描电镜(SEM)以及透射电镜(TEM)等方法对人工时效状态下新型高强韧铝锂合金厚板室温拉伸性能、热稳定性、断口形貌以及微观组织进行了研究。结果表明，合金进行室温拉伸试验时，厚板T/2厚度位置处的强度和伸长率均高于T/4厚度位置，这是由于板材进行轧制变形时，T/2厚度位置处变形量较大，位错密度更高，后续时效处理时会析出更多的强化相；稳定化时间一定时，随稳定化温度的升高，合金强度先增加，稳定化温度超过175℃后，强度逐渐降低，合金的热稳定性主要取决于稳定化处理后析出相的变化，稳定化温度低于150℃时，T₁相具有较好的耐热性，析出相的尺寸和数量变化较小，稳定化温度进一步升高后，T₁相数量逐渐减少。

Microstructure and properties of a new-type high strength and toughness Al-Li alloy

Room temperature tensile properties, thermal stability, fracture morphology and microstructure of a new-type high strength and toughness Al-Li alloy thick plate under artificial aging condition were studied by means of tensile test, thermal stabilization test, scanning electron microscope(SEM) and transmission electron microscope(TEM).The results show that the tensile strength, yield strength and elongation of the alloy plate at T/2 thickness are higher than those at T/4 thickness at room temperature. This is because the deformation at T/2 thickness is larger and the dislocation density is higher, and more strengthening phase is precipitated during subsequent aging treatment. When the stabilization time is constant, the strength of the alloy increases at first with the increase of stabilization temperature. While the stabilizing temperature exceeds 150 ℃, the strength decreases significantly, the thermal stability of the alloy is mainly depends on the change of the precipitated phase. When the stabilization temperature is below 150 ℃, the T₁ phase keeps a good heat resistance, the size and quantity of precipitated phase change slightly. When the stabilization temperature rises further, the number of T₁ phase decreases gradually.