Effect of Heat Treatment on Positron Annihilation Lifetime of an Extruded Al-12.7Si-0.7Mg Alloy

Abstract:

Positron annihilation lifetime can reflect the information of electronic density. Therefore this technique is very sensitive to the vacancies. Therefore positron annihilation technology (PAT) is a non-destructive testing technology for the investigation on the vacancy in pure metals and alloys. The vacancy defects of as-cast pure aluminium and the extruded Al-12.7Si-0.7Mg alloy before and after heat treatment were investigated by positron annihilation lifetime spectra. The results of positron annihilation lifetime spectra show that the lifetime of free positron annihilation in the pure aluminium alloy is 155 ps. The positron annihilation lifetime of the extruded sample is longer than the lifetime in the pure aluminium due to the formation of grain boundary and dislocation during the extrusion process. The positron annihilation lifetime of the extruded sample after heat treatment is shorter than that before the heat treatment, and it is longer than that of the pure sample.

• Periodical: Materials Science Forum (Volume 788)
• Pages: 258-261
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.788.258
• Online since: April 2014
• Authors: Yan Hui Zhang*, Dong Wang, Chang Shu He, Xing Zhong Cao, Lin Zhang
• Keywords: Al-Si Alloy, Extrusion, Heat Treatment, Positron Annihilation Lifetime

References

[1] Shi W X, Gao B, Tu G F, Li S W, Hao Y, Yu F X, Effect of neodymium on primary silicon and mechanical properties of hypereutectic Al-15%Si alloy, Journal of Rare Earths. 28S1 (2010) 367-370.

DOI: 10.1016/s1002-0721(10)60363-8

[2] Yu F X, Cui J Z, Qin K, Sun Z G, Wang H. China Patent 200510119550. 6, (2008)

[3] Zuo L, Yu F X, Zhao G, Zhao X, Yang Y L, Li Y. China Patent 200810137603. 0, (2010)

[4] Liu Fang, Yu Fuxiao, Zhao Dazhi, Zuo Liang, Microstructure and mechanical properties of an Al–12.7Si–0.7Mg alloy processed by extrusion and heat treatment Materials, Science and Engineering A. 528 (2011) 3786-3790.

DOI: 10.1016/j.msea.2011.01.041

[5] Hong Tao, Gong Yuanping, Tian Ni, Zhao Gang, Yu Fuxiao, Zuo Liang, Effect of Solution Temperature on Microstructure and Properties of Al-12．7Si-0．7Mg Aluminum Alloy Extrusion, Chinese Journal of Rare Metals. 3 (2012) 368-372.

[6] Doyama M, Cotterill R M J, Proc 5th Int. Conf. Positron Annihilation Japan. 89 (1979)

[7] Hautojarvi P. He Y J, Yu W Z (Eds.), Positrons in solids, Trans Tech Publications Publishing Inc., Beijing, 1983.