Preparation of High Strength Aluminum Alloys by Rapid Solidification Processing and Analyses of Structural Change

Research Project

Project/Area Number	60550506
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	Tokyo Institute of Technology
Principal Investigator	MURAKAMI Takeshi (1986) Tokyo Institute of Technology , Assistant, 工学部, 助手 (60016681) 高橋恒夫 (1985) 東京工業大学, 工学部, 教授
Co-Investigator(Kenkyū-buntansha)	SATO Tatsuo Tokyo Institute of Technology , Assistant, 工学部, 助手 (90126318) TAKAHASHI Tsuneo Chiba Institute of Technology , Professor, 工学部, 教授 (90016189)
Project Period (FY)	1985 – 1986
Project Status	Completed (Fiscal Year 1986)
Budget Amount *help	¥1,900,000 (Direct Cost: ¥1,900,000) Fiscal Year 1986: ¥200,000 (Direct Cost: ¥200,000) Fiscal Year 1985: ¥1,700,000 (Direct Cost: ¥1,700,000)
Keywords	Rapid Solidification / Melt Spinning / Aluminum Alloys / Decomposition / 機械的性質
Research Abstract	In order to obtain informations necessary for exploration of high strength aluminum alloy by means of powder metallurgy, rapidly-solidified structures and decomposition process in Al-Fe and Al-Fe-Ce alloys were investigated. Obtained results are summarised as follows; 1. In an Al-Fe alloy, the solid solubility of iron extends up to 7.3 mass % at a cooling rate about <10^6> K/s. Cell structures was observed in the alloys solidified at a cooling rate about <10^5> K/s. Cell boundaries were composed of aggregates of metastable phase <Al_6Fe> . In the decomposition process of rapidly-solidified Al-7 mass % Fe alloy, following three metastable phases were observed; an angular-shaped metastable phase with diamond cubic structure, a disc-shaped metastable phase and a rod-shaped metastable phase with f.c.c. structure. 2. In Al-4 mass % Fe-1-4 mass % Ce alloys, fine metastable phases coherent with the matrix were formed during rapid solidification. Upon annealing, ternary metastable phase with cubic structure precipitated parallel to<100> of the matrix. At a cooling rate about <10^5> K/s, cell structures were formed in an Al-4 mass % Fe-4 mass % Ce alloy. Fine dispersoids in cell boundaries were identified as <Al_8CeFe_4> equilibrium phase by electron diffraction. 3. Softening was not detected by hardness test of ribons even after holding at 300 ゜C for 1 hr in both Al-Fe and Al-Fe-Ce alloys. It was found that the addition of cerium to Al-Fe alloys is effective to increase thermal stability of this alloy.