采用多块均匀分布过剩TiH2的球形孔泡沫铝合金作为坯料置于异型件模具中, 用二次泡沫化方法制备出具有均匀孔结构的高孔隙率泡沫铝合金合金异型件. 用光学显微镜和层析X射线成像仪(X--CT)观察异型件的冶金结合界面结构, 并对异型件冶金结合界面的拉伸性能进行了实验研究. 结果表明, 采用二次发泡方法在发泡温度700--900℃、发泡时间250--800 s条件下, 可以实现泡沫铝合金的有效冶金结合; 形成的异型件结合界面连接机制分为界面机械连接与界面扩散连接; 泡沫铝合金异型件冶金结合面的抗拉强度随着孔隙率的升高而降低, 泡沫铝合金异型件的孔隙率为74.9\%时, 结合界面处抗拉强度与泡沫铝合金的本体强度相当.
Equal high porosity shaped Al alloy foam were fabricated by metallurgy bonding of Al alloy foam flans in the shaped mould with enough equal TiH2 powder by two--step foaming (TSF) method. The microstructure of bonding joint between Al alloy foam was observed by using stereo--microscope and X--CT, and the tensile strength of the bonding joint was tested. The results show that the optimized temperature and foaming time for appropriate bonding are 700--900℃ and 250--800 s, respectively. The interface mechanical joining and the interface diffusion dominate the bonding mechanisms of Al alloy foam by TSF method. The metallurgy bonding tensile strength of shaped Al alloy foam increases with the decrease of the porosity of Al alloy foam, and the bonding strength is close to the Al alloy foam matrix when the porosity rises to 74.9%.
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