Microstructural evolution of 6063 aluminum during friction-stir welding

Journal Article · Wed Sep 01 04:00:00 EDT 1999 · Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science

DOI:https://doi.org/10.1007/s11661-999-0251-1· OSTI ID:684460

Sato, Y S; Kokawa, Hiroyuki ^[1]; Enomoto, Masatoshi ^[2]; Jogan, Shigetoshi ^[3]

---

1. Tohoku Univ., Sendai (Japan). Dept. of Materials Processing
2. Showa Aluminum Corp., Oyama City, Tochigi (Japan)
3. Showa Aluminum Corp., Sakai, Osaka (Japan)

The microstructural distribution associated with a hardness profile in a friction-stir-welded, age-hardenable 6063 aluminum alloy has been characterized by transmission electron microscopy (TEM) and orientation imaging microscopy (OIM). The friction-stir process produces a softened region in the 6063 Al weld. Frictional heating and plastic flow during friction-stir welding create fine recrystallized grains in the weld zone and recovered grains in the thermomechanically affected zone. The hardness profile depends greatly on the precipitate distribution and only slightly on the grain size. The softened region is characterized by dissolution and growth of the precipitates during the welding. Simulated weld thermal cycles with different peak temperatures have shown that the precipitates are dissolved at temperatures higher than 675 K and that the density of the strengthening precipitate was reduced by thermal cycles lower than 675 K. A comparison between the thermal cycles and isothermal aging has suggested precipitation sequences in the softened region during friction-stir welding.

• Sponsoring Organization: USDOE
• OSTI ID: 684460
• Journal Information: Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science, Journal Name: Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science Journal Issue: 9 Vol. 30; ISSN 1073-5623; ISSN MMTAEB
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM BASE ALLOYS
CORRELATIONS
FRICTION WELDING
HARDNESS
MICROSCOPY
MICROSTRUCTURE
PRECIPITATION
SIMULATION