旋转速度对滚动摩擦沉积增材组织的影响

Effect of rotational velocity on additive structure of rolling friction deposition

滚动摩擦沉积增材(Additive Friction Rolling Deposition,AFRD)是一种新兴的金属固态增材制造技术,特别适用于基于熔合增材制造方法易产生凝固缺陷的高强度铝合金。采用AFRD方法进行2024-O铝合金增材,获得全致密无缺陷的四层增材试件,利用金相显微镜、扫描电子显微镜对不同旋转速度增材试件宏观形貌、微观组织进行了表征。结果表明:(1)沉积层组织致密,无夹杂、裂纹等缺陷、相邻两沉积层之间形成良好的冶金结合。(2)沉积层呈现细小的轴晶粒组织,随着旋转速度升高,晶粒尺寸呈下降趋势。(3)沉积层第二相粒子呈现点片状分布于Al基体上,随着转速增大,第二相粒子趋向于细化与均匀。

Additive Friction Rolling Deposition(AFRD)is a new metal solid additive manufacturing technology,which is especially suitable for high strength aluminum alloys that are prone to solidification defects based on fusion additive manufacturing.In this paper,the 2024-O aluminum alloy was augmented by AFRD method,and a fully dense,defect-free four-layer additive specimen was obtained.Metallographic microscopy and scanning electron microscopy were used to characterize the macro morphology and microstructure of the additive specimens with different rotation speeds.The results show that:(1)the structure of the deposit is dense,there are no defects such as inclusions and cracks,and a good metallurgical bond is formed between the two adjacent deposits.(2)The sedimentary layer presents fine equiaxed grain structure,and the grain size decreases with the increase of rotation speed.(3)The second phase particles in the sedimentary layer are distributed on the Al matrix in spots,and the second phase particles tend to be refined and uniform with the increase of rotational speed.