Origin of Insignificant Strengthening Effect of CNTs in T6-Treated CNT/6061Al Composites

• DOI: 10.1007/s40195-017-0626-z
• Publication Date: 2017-07-08T03:19:27Z
• Authors: Ke Zhao; Zhen-Yu Liu; Bo-Lyu Xiao; Ding-Rui Ni; Zong-Yi Ma
• Keywords: Friction Stir Processing; Powder Metallurgy

Carbon nanotube (CNT)-reinforced 6061Al (CNT/6061Al) composites were fabricated via powder metallurgy combined with friction stir processing (FSP). CNTs were dispersed after FSP and accelerated the precipitation process of the CNT/6061Al composites. However, the strengthening effect of CNTs on the T6-treated materials was insignificant, while the composites under the FSP and solution treatment conditions exhibited increased strength compared to the matrix. Precipitate-free zones (PFZs) were detected around CNTs in the T6-treated CNT/6061Al composites, and a model was proposed to describe the effect of PFZs on strength. The calculations indicated that the strength of PFZs was similar to that of the T6-treated 6061Al. As a result, the strengthening effect of CNTs on the T6-treated CNT/6061Al composites was insignificant.