Premium
Gefüge und Ermüdungsverhalten rührreibgeschweißter artfremder Verbindungen der Aluminiumlegierungen 2A12‐T4 und 7075‐T6
Author(s) -
Zhang D.F.,
Tang Q.Y.,
Wei T.H.,
Lin Y.H.,
Chen X.W.,
Xia J.
Publication year - 2020
Publication title -
materialwissenschaft und werkstofftechnik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.285
H-Index - 38
eISSN - 1521-4052
pISSN - 0933-5137
DOI - 10.1002/mawe.201900113
Subject(s) - materials science , equiaxed crystals , welding , joint (building) , microstructure , metallurgy , fracture (geology) , indentation hardness , base metal , alloy , grain size , aluminium , friction stir welding , paris' law , heat affected zone , composite material , fracture mechanics , structural engineering , crack closure , engineering
The objective of this work is to investigate the microstructure and fatigue performance of friction stir welding joint of 2A12‐T4 and 7075‐T6 dissimilar aluminum alloy. Microstructure shows that the grain growth of heat‐affected zone in both sides of joint is noticeable; the grain size of thermo‐mechanically affected zone in both sides of joint is deformed and distorted in various degrees; nugget zone is fine equiaxed grain with uniform distribution. Microhardness of joint presents an approximate “W” types distribution on the whole, and the highest hardness value of the joint appears near the center of nugget zone, up to 146.5 HV0.2. Since the joint has the higher the fatigue strength ratio, and the S−N curve of the joint shows a smaller downward trend, the joint has the best fatigue performance and 7075‐T6 base metal has the worst fatigue performance. Linear fitting of 7075‐T6 base metal is l n S = - 0 . 172 l n N + 7 . 47812 ; linear fitting of 2A12‐T4 base metal is l n S = - 0 . 189 l n N + 7 . 54361 ; linear fitting of joint is l n S = - 0 . 161 l n N + 7 . 07129 . The fracture analysis presents that the low‐cycle fatigue fracture mechanism of welding joint is quasi‐cleavage fracture, and the main mode of high cycle fatigue fracture is the inter crystalline fracture, mixed with ductile fracture.