Inprovement of mechanicahl properties of Al-Li-Zr alloys due to the promoted formation of composite precipitates by using rapid solidification technology

Research Project

Project/Area Number	62550530
Research Category	Grant-in-Aid for General Scientific Research (C)
Allocation Type	Single-year Grants
Research Field	金属材料(含表面処理・腐食防食)
Research Institution	Kanasai Uviversity
Principal Investigator	MURAKAMI Yotaro Department of Metallurgical Engineering, Kansai University, 工学部, 教授 (90025750)
Co-Investigator(Kenkyū-buntansha)	NAKAO Kazuyoshi 関西大学, 工学部, 助手 (40067632) AKAMATSU Katsuya 関西大学, 工学部, 教授 (70067643)
Project Period (FY)	1987
Project Status	Completed (Fiscal Year 1987)
Budget Amount *help	¥1,900,000 (Direct Cost: ¥1,900,000) Fiscal Year 1987: ¥1,900,000 (Direct Cost: ¥1,900,000)
Keywords	Al-Li-Zr Alloys / Rapid Solidification / Hot Compaction / Hot Extrusion / Double Ageing / TEM obserbation / Composite Precipitation / 機械的性質 / Al-Li-Zr系合金 / 複合析出物
Research Abstract	The composition of the plloys in this investigation are Al-Li alloys containing 4 Wt% Li with or without 1 wt% Zr. The alloys rapidly quenched from the melt into continuous ribbons using jet casting process by single and twin rolls. these ribbons were mechanichally comminuted to fine powder and then consolidated into bulk compacts by vacuum hot pressing and hot extrusion to wires of 2.0mm in diameter(20:<iota> extrusion tatio). These wires were further drown to wires of 1.5 and 1.6mm in diameters. The were specimes were age-treated in the following;(a) as-drown,(b) pre-aged, 500゜Cx2hrs,(c) single-aged, 190゜Cx16hrs,(d) double-aged, 500゜Cx2hrs+190゜Cx16hrs,(e) doule-aged, 500゜Cx72hrs+190゜Cx16hrs. The age-treated specimens were examind by a transmission electron microscope in order to clarify the nature, size and distribution of precipitatrs. It was found that double-ageing is very effective to the formation of composite precipitates, which is a continuous envelope of <delta>'Al_3Li surrounding the <alpha>'-Al_3Zr. The present investigation has shown that the enganced mechanical properties that were obtained were mainly due to the promoted precipitaition of composite precipitete.