轧制轧制工艺对粉末复合轧制法制备泡沫铝孔结构的影响

Influence of rolling process on pore structure of aluminum foam prepared by powder composite rolling method

以铝粉、硅粉为基体粉末,以TiH2为发泡剂,通过粉末复合轧制法制备泡沫铝,并采用扫描电镜、能谱仪、X射线衍射方法分析泡沫铝前驱体的微观组织成分、泡沫铝宏观形貌和孔结构参数,研究不同轧制工艺下泡沫铝的孔结构特性。研究结果表明:随着轧制变形量的增加,泡沫铝前驱体中Si/Ti金属粉末在基体中的分散性提高,致密化程度提升;发泡后孔壁厚度与轧制变形量成反比,实体区域面积随着轧制变形量的增加而增加;随着轧制温度升高,泡沫铝发泡时间更短,膨胀率更高,发泡程度更高;在轧制温度500℃下,前驱体中基体粉末结合更紧密,粉末间隙减小,前驱体致密层厚度及硬度小,且发泡过程气体扩散动力大,发泡后形成的实体层面积小、试样泡孔壁厚度变薄、圆度值更高;粉末复合轧制法制备泡沫铝在轧制温度500℃、轧制变形量60%下具有最优的孔结构特性。

Taking aluminum powder and silicon powder as matrix powder and TiH_2 as foaming agent,the aluminum foam was prepared by powder composite rolling method.Then,the microstructure composition of aluminum foam precursor,macroscopic morphology and pore structure parameters of aluminum foam were analyzed by SEM,EDS and XRD,and the pore structure characteristics of aluminum foam under different rolling processes were studied.The results show that with the increasing of rolling deformation,the dispersion of Si/Ti metal powder in the matrix of aluminum foam precursor is improved,and the densification degree is improved.After foaming,the wall thickness of pore is inversely proportional to the rolling deformation,and the area of solid area increases with the increasing of rolling deformation.With the increasing of rolling temperature,the foaming time of aluminum foam is shorter,the expansion rate is higher,and the foaming degree is higher.At the rolling temperature of 500°C,the matrix powder in the precursor is more closely bonded,the powder gap is reduced,the thickness and hardness of dense layer for precursor are small,and the gas diffusion power in the foaming process is large.After foaming,the solid layer area is small,the wall thickness of foam pore for sample becomes thinner,and the roundness value is higher.The aluminum foam prepared by the powder composite rolling method has the best pore structure characteristics at the rolling temperature of 500°C and the rolling deformation of 60%.