Influence of Retrogression and Reaging Treatment on Microstructure and Microhardness of the 3A21/7075 Aluminum Alloy Cladding Material

Table 1

Chemical composition of the 7075 and the 3A21 (mass fraction, %).

Material	Si	Fe	Cu	Mn	Mg	Cr	Zn	Ti	Other	Al
7075	0.4	0.5	1.2~2.0	0.3	2.1~2.9	0.18~0.28	5.1~6.1	0.20	0.20	Bal.
3A21	0.6	0.7	0.2	1.0~1.6	0.05	—	0.1	0.15	0.15	Bal.