Positron lifetime and Doppler Broadening study of defects with hydrogen loaded in Al-Mg alloys
The investigation of Positron lifetime and Doppler Broadening of defects with the hydrogen loaded in non-heat treatable 5xxx Al alloys was presented in this work. The yield stress of the sample were decreased about 20 MPa after hydrogen loaded. Corresponding to Positron lifetime measurement, the average lifetime τav was descended very remarkably almost to be closed to the level of Al matrix. The variation of coincidence Doppler-broadening spectroscopy was also very obvious. The CDB radio curve exhibited the characteristic shape of sample before and after hydrogen loaded. In the hydrogen loaded sample, the obvious enhancement in the high-momentum region compensating dehancement in the low momentum region means the existence of hydrogen filling effect. These results show that the hydrogen will be harmful factor for mechanical properties of the non-heat treatable 5xxx Al alloys. The vacancies around Mg atoms should be a preferential filling position for hydrogen because Mg has a strong affinity for hydrogen. The formation of Mg-H bond parallel to a grain boundary is also an important factor in weakening the grain boundary cohesion.
Xiaowei WANG Yurong Zhong Baoyi WANG Hongyan Zhang
Shenyang National Laboratory for Materials Science,Institute of Metal Research,Chinese Academy of Sc Institute of High Energy Physics,Chinese Academy of Sciences,P.O.Box 918,Beijing 100039,Peoples Rep Department of MIME,University of Toledo,Toledo,OH 43606,USA
国际会议
第九届国际正电子与正电子素国际会议(9th International Workshop on Positron and Positronium Chemistry)(PPC–9)
武汉
英文
129
2008-05-11（万方平台首次上网日期，不代表论文的发表时间）