Process of solution treatment of 2024 aluminum alloy was done by hardness test and microanalysis in this paper. The effects of different solution treatment temperature on the microstructure and mechanical properties of 2024 aluminum alloy were studied and the influence of overburning on the microstructure and mechanical properties of 2024 aluminum alloy were also analyzed. The experimental results show that overburning occurs while 2024 aluminum alloy is heated over 490°C×50min . The hardness tests and microstructure analysis results show that the hardness decreased, grain boundary becomes trigemanal and compounded –melting structure (burnt structure) appeared when overburning occuring for this alloy .

Finite element simulation of the effects of mould angle and friction condition on the equal channel angular pressing (ECAP) for AZ80 magnesium alloy were investigated by using DEFORM-3D program. The results show that the curve of load-displacement was divided into several stages including rapid increasing stage, load fluctuation, rapid increasing stage, steady stage and rapid drop stage. Firstly, when the angle decreased from 150°to 90°, the maximum load increased, and the same as energy consuming. In addition, the average effective strain increased with the decreasing of mould angle after single extrusion, while the degree of effective strain uniformity of the sample decreased and keep greater strain grads between inner and surface part. Secondly, the work load ascended with the increasing of the friction coefficient from 0 to 0.3, and one part of load overcome the friction and the other part is used for deformation of the sample. With the increment of friction coefficient, the average effective strain keeps steady value, while the degree of effective strain uniformity of the sample decreased. As mentioned above, large angle mould and low coefficient of friction should be adopted during ECAP deformation for AZ80 magnesium alloy.

The thermomechanical treatment of a 2A12 aluminum alloy was researched and the influence of pre-ageing on microstructure and hardness was analyzed emphatically. The results reveal that the hardness of specimen increases when they are pre-aged, the hardness value rises at first and then decreases, reaching the maxmum value when pre-aged at 180°C×30min . After plastically deformed at 450°C, the hardness keeps on increasing, and the grains are equiaxed polygon structure. After all the workpieces are aged in the end, the small particles of the second phase precipitates completely and disperses within the original phase matrix, the particles interact with dislocations in upper state that formed during plastic deformation and lead to a great increase in hardness compared with as-received. the best pre-aging parameter is 180°C×30min.

Process of solution treatment of 6061 aluminum alloy was done by hardness test and microanalysis in this paper. The effects of different solution treatment temperature on the microstructure and mechanical properties of 6061 aluminum alloy were studied and the influence of overburning on the microstructure and mechanical properties of 6061 aluminum alloy were also analyzed. The experimental results show that overburning occurring while 6061 aluminum alloy is heated above 580°C . The hardness measurements and microstructure analysis results show that the hardness decreased, grain boundary becomes trigemanal and compounded –melting structure (burnt structure) appeared when overburning occuring for this alloy .

Calculating stress intensity factor is an important task of fracture mechanics, specially in the thick walled cylinder with inner pressure, which has macro crack. The value of KІ is crucial for safety life. The software ANSYS was used to calculate the stress intensity factors of the walled cylinder in this paper. Crack along the axis in the inner face of the tube can be predigested a long plate with a center crack. According to the symmetry of this model, the calculated model was built. The results show that the relative error is under 5% and the method is available to satisfy the precision engineering requirements. In addition, the error and how to reduce it were analyzed.