Microstructure and fracture characteristics of rapidly solidified AiLiMg alloys containing 4 and 5 wt.% Li

✍ Scribed by Marie-Christine Gaillard; John A. Wert

• Publisher: Elsevier Science
• Year: 1990
• Tongue: English
• Weight: 949 KB
• Volume: 125
• Category: Article
• ISSN: 0921-5093
• DOI: 10.1016/0921-5093(90)90257-4

✦ Synopsis

The microstructure and fracture characteristics of rapidly solidified AI-Li-Mg alloys containing 4-5 wt. % Li and 6.5-10 wt. % Mg have been evaluated. Rapid solidification suppressed the formation of constituent phases during solidification, although Al3Li precipitated from solid solution after solidification. The alloys were then annealed at 673 K to simulate the hot-degassing treatment normally performed prior to final consolidation of powder metallurgy aluminum alloys. Dissolution of the metastable Al~Li and precipitation of the equilibrium Al2LiMg phase occurred during annealing at 673K. Fractographic analyses showed that the fracture mechanism in alloys containing 0.23 or less volume fraction of Al2LiMg phase is microvoid coalescence, while the alloy with 0.35 volume fraction of Al2LiMg failed by a brittle fracture mechanism involving interphase decohesion and/or cleavage of the intermetallic phase.