New quaternary grain boundary precipitate in Al–Mg–Si alloy containing silver

It is known that a lamellar discontinuous precipitate forms in aged Cu-1.8wt.% Be alloys. The purpose of this study was to investigate factors which influence the formation of the precipitate and to characterize its growth.To determine the effect of solution treatment on the discontinuous precipitate, specimens were solution treated at 800°C, 850°C, and 900°C for 1 hour followed by an ice water quench. Some of the solution treated specimens were examined in the as-quenched condition. The remaining specimens were aged at 340°C for 24 hours. The specimens were thinned with a twin-jet electropolishing unit using 30% HNO3 in methanol at -60°C. The specimens were then examined using either an RCA-EMU3G or a Philips EM-300 electron microscope.Each solution treated specimen was not single phase, but showed some residual grain boundary precipitate which implies that the solution anneal was not sufficient, or else precipitation had occurred during quenching. The higher solution treatment temperatures slightly reduced the amount of this grain boundary precipitate, but none completely removed it, even after five hours at temperature,indicating quench decomposition as the mechanism responsible.

Download Full-text

Grain Boundary Precipitate Modification for Improved Intergranular Corrosion Resistance

Materials Science Forum - Aluminium Alloys 2006 ◽

10.4028/0-87849-408-1.327 ◽

2006 ◽

pp. 327-332

Author(s):

Kinga A. Unocic ◽

Paul Kobe ◽

Michael J. Mills ◽

Glenn S. Daehn

Keyword(s):

Corrosion Resistance ◽

Grain Boundary ◽

Intergranular Corrosion ◽

Boundary Precipitate ◽

Intergranular Corrosion Resistance

Download Full-text

Grain boundary-precipitate interactions in γ′ Ni3(Al,Ti)

Scripta Metallurgica et Materialia ◽

10.1016/0956-716x(95)00158-r ◽

1995 ◽

Vol 33 (1) ◽

pp. 1-6 ◽

Cited By ~ 3

Author(s):

V. Gehanno ◽

M.-L. Turi ◽

G.C. Weatherly ◽

G.R. Purdyn

Keyword(s):

Grain Boundary ◽

Boundary Precipitate

Download Full-text

Correlation of grain boundary precipitate characteristics with fracture and fracture toughness in an Mg-8Al-0.5 Zn alloy

Materials Science and Engineering A ◽

10.1016/j.msea.2017.09.019 ◽

2017 ◽

Vol 706 ◽

pp. 192-200 ◽

Cited By ~ 13

Author(s):

A. Zindal ◽

J. Jain ◽

R. Prasad ◽

S.S. Singh ◽

P. Cizek

Keyword(s):

Fracture Toughness ◽

Grain Boundary ◽

Boundary Precipitate ◽

Zn Alloy

Download Full-text

Grain Boundary Precipitation and Tensile Ductility of Fe-Mn-Ni Alloys

Materials Science Forum ◽

10.4028/www.scientific.net/msf.539-543.1595 ◽

2007 ◽

Vol 539-543 ◽

pp. 1595-1600 ◽

Cited By ~ 3

Author(s):

Yoon Uk Heo ◽

Seung Ho Mun ◽

Hu Chul Lee

Keyword(s):

Grain Boundary ◽

Tensile Ductility ◽

Aging Treatment ◽

Boundary Precipitate ◽

Intermetallic Particles ◽

Ni Alloy ◽

Alloy Addition ◽

Stable Austenite ◽

Grain Boundary Embrittlement ◽

Boundary Embrittlement

The mechanism of grain boundary embrittlement and the improvement of the tensile ductility afforded by alloy addition or heat treatment was investigated in an Fe-Mn-Ni alloy. The precipitation of θ-MnNi intermetallic particles was observed at the prior austenite or interlath boundaries during the aging treatment and this was believed to be responsible for the grain boundary embrittlement of these alloys. After prolonged aging or aging at higher temperatures above 520°C, these metastable intermetallic particles were transformed into the thermodynamically stable austenite phase, thereby leading to the recovery of the grain boundary strength. The addition of Mo caused the grain boundary precipitate to be changed to austenite and resulted in a significant improvement in the tensile ductility after aging.

Download Full-text