材料期刊网

放电合金化工艺在 AA6082 Al-Mg-Si 铝合金表面涂覆自润滑碳化物层的形成和表征

Wang-Chih CHEN , Hung-Mao LIN , Jun-Yen UAN

中国有色金属学报(英文版) doi:10.1016/S1003-6326(16)64453-9

采用放电合金化工艺对 AA6082 Al?Mg?Si 时效硬化铝合金进行表面改性。在放电合金化过程中，作为工作液的煤油热解成碳，从而形成附着于合金表面的自润滑碳化物层。TEM 结果表明，合金表面形成的自润滑碳化物层为由碳化物和石墨组成的多相材料。因此，经放电合金化改性铝合金的摩损率极小，约为2×10?4 mg/m，而铝合金基体的磨损率约为1.1×10?2 mg/m。显然，在铝合金表面经放电合金化形成的碳化物为一种能改善合金抗电磁干扰性能的软磁体。

关键词: Al-Mg-Si 铝合金 , 表面改性 , 放电合金化 , 自润滑 , 热解碳 , 抗电磁干扰性能

A Study of Submicron Grain Boundary Precipitates in Ultralow Carbon 316LN Steels

Metallurgical and Materials Transactions a-Physical Metallurgy and Materials Science

This article reports our efforts in characterization of an ultralow carbon 316LN-type stainless steel. The carbon content in the material is one-third that in a conventional 316LN, which further inhibits the formation of grain boundary carbides and therefore sensitizations. Our primary effort is focused on characterization of submicron size precipitates in the materials with the electron backscatter diffraction (EBSD) technique complemented by Auger electron spectroscopy (AES). Thermodynamic calculations suggested that several precipitates, such as M(23)C(6), Chi, Sigma, and Cr(2)N, can form in a low carbon 316LN. In the steels heat treated at 973 K (700 A degrees C) for 100 hours, a combination of EBSD and AES conclusively identified the grain boundary precipitates (a parts per thousand yen100 nm) as Cr(2)N, which has a hexagonal closed-packed crystallographic structure. Increases of the nitrogen content promote formation of large size Cr(2)N precipitates. Therefore, prolonged heat treatment at relatively high temperatures of ultralow carbon 316LN steels may result in a sensitization.

关键词: electron backscatter diffraction;austenitic stainless-steels;m23c6;carbide;microstructure;temperature;toughness;evolution

R & D OF HYDROGEN ABSORBING ALLOYS IN JAPAN

K. Mii (Sumitomo Metal Industries , Ltd. , 1-t-3 Otemachi , Tokyo 100 , Japan)M Amano (National Research Institute for Metals , 1-2-1 Sengen , Tsukuba 305 , Japan)

金属学报(英文版)

The R & D of hydrogen absorbing alloys in Japan started in the early 1970s.Many alloys such as TiMm1.5 based alloys, Fe-Ti-O alloys (e.g. FeTi1.15 O0.024) andthe(mischmetal)Ni5 based alloys (e.g. MmNi4.5 Cr0.46 Mn0.04) were developed by the early 1980s. The application of these alloys to hydrogen storage, heat storage, heat pump, hydrogen purification and motor vehicles has been tried in many iaboratories,and the various techniques for using hydrogen absorbing alloys have been developed.The standarkization of evaluation methods for hydrogen absorbing alloys has been promoted by the Ministry of International Trade and Industry (MITI), and four of them were established as Japanese Industrial Standard (JIS).Alloys for Ni-Metal Hydride batteries have been extensively investigated since 1987in Japun. Mm-Ni-Co-Al-Mn alloys (e.g. MmNi3.55 Co0.75Al0.9Mn0.4) have been devel-oped and commereialized since 1990. The amount of production of small-size Ni-MH batteries in 1995 was about three hundred milliion in number and about one hundred billion yen. The R & D for higher enerpy-density Ni-MH batteries is intensively in progress.MITI and STA (Science and Technology Agency) have promoted the R & D of hydro-gen absorbing alloys in Japan by carrying out the national projects such as Sunshine Program (MITI: 1974-1993) and Utilization of Wind Engeray (STA 1980-1985). The New Sunshine Program (MITI 1993-2020) have started in 1993. This program con-tains the application of hydrogen absorbing alloys to Economical- Enerpy- City System and to We-NET (International Clean Energy System of Technology Utilizing Hydro-gen: World Energy Network.

关键词: hydrogen absorbing alloy , null , null , null