攪拌摩擦加工CNTs/7075鋁基復合材料 熱膨脹性能攪拌摩擦加工CNTs/7075鋁基復合材料 熱膨脹性能Thermal expansion characteristic of CNTs/7075 aluminum alloy composites prepared by friction stir processing 采用攪拌摩擦加工法制備CNTs/7075鋁基復合材料，測量并分析加工態、熱處理態試樣的熱膨脹系數，并分別用ROM、Turner和Schapery模型進行理論計算。結果表明：攪拌摩擦加工后材料的晶粒細小，CNTs的添加能進一步細化晶粒。CNTs/7075復合材料的熱膨脹系數低于退火態和攪拌摩擦加工后7075鋁合金試樣的，說明攪拌摩擦加工對材料晶粒的細化及CNTs的加入可以有效地約束基體材料的熱膨脹，且隨著CNTs含量的增加，復合材料的線膨脹系數呈減小趨勢。后續熱處理對CNTs/7075復合材料的熱膨脹系數也有影響，退火和固溶時效處理均可以降低該復合材料的熱膨脹系數。理論計算發現，Turner模型計算得到的熱膨脹系數預測值最接近于實測值。 7075 aluminum alloy based composite reinforced with carbon nanotubes was prepared by friction stir processing. The thermal expansion coefficients of CNTs/7075 composites with processed state and heat treatment were measured. And the theoretical thermal expansion coefficient of CNTs/7075 composite was calculated with ROM, Turner and Schapery’s model. The results show that the grain size of material can effectively reduced by friction stir processing, and the addition of CNTs can further refine grain size of composite. The CNTs/7075 composite has smaller thermal expansion coefficients compared with annealed 7075 matrix materials and the FSPed 7075 samples, which indicates that the addition of CNTs can effectively constrain the thermal expansion of the composite. The thermal expansion coefficients of CNTs/7075 composite samples decrease along with the increase of volume fraction of CNTs. Heat treatment has a positive effect on the thermal expansion characteristic of the composite, and the annealing or aging treatment can decrease the thermal expansion of the composite. The theoretical calculation shows that thermal expansion coefficient of CNTs/7075 composite with Turner’s model is the closest to the experimental result.
|
