Effect of Hydrogen on Corrosion and Stress Corrosion Cracking of AZ91 Alloy in Aqueous Solutions  

作　　者：Jian Chen Jian-Qiu Wang En-Hou Han Wei Ke D.W.Shoesmith 

机构地区：[1]Department of Chemistry,Western University [2]Surface Science Western,Western University [3]Key Laboratory of Nuclear Materials and Safety Assessment,Institute of Metal Research,Chinese Academy of Sciences

出　　处：《Acta Metallurgica Sinica(English Letters)》2016年第1期1-7,共7页金属学报（英文版）

基　　金：supported by the Hundred Talent Program of the Chinese Academy of Sciences,the National Natural Science Foundation of China(No.50499336);the National Basic Research Program of China(No.2007CB613705)

摘　　要：The effect of hydrogen on the corrosion and stress corrosion cracking of the magnesium AZ91 alloy has been investigated in aqueous solutions. Hydrogen produced by corrosion in water diffuses into, and reacts with the Mg matrix to form hydride. Some of the hydrogen accumulates at hydride/Mg matrix （or secondary phase） interfaces as a consequence of slow hydride formation and the incompatibility of the hydride with the Mg matrix （or secondary phase）, and combines to form molecular hydrogen. This leads to the development of a local pressure at the hydride/Mg matrix （or secondary phase） interface. The expansion stress caused by hydride formation and the local hydrogen pressure due to its accumulation result in brittle fracture of hydride. These two combined effects promote both the corrosion rate of the AZ91 alloy, and crack initiation and propagation even in the absence of an external load. Hydrogen absorption leads to a dramatic deterioration in the mechanical properties of the AZ91 alloy, indicating that hydrogen embrittlement is responsible for transgulanar stress corrosion cracking in aqueous solutions.The effect of hydrogen on the corrosion and stress corrosion cracking of the magnesium AZ91 alloy has been investigated in aqueous solutions. Hydrogen produced by corrosion in water diffuses into, and reacts with the Mg matrix to form hydride. Some of the hydrogen accumulates at hydride/Mg matrix （or secondary phase） interfaces as a consequence of slow hydride formation and the incompatibility of the hydride with the Mg matrix （or secondary phase）, and combines to form molecular hydrogen. This leads to the development of a local pressure at the hydride/Mg matrix （or secondary phase） interface. The expansion stress caused by hydride formation and the local hydrogen pressure due to its accumulation result in brittle fracture of hydride. These two combined effects promote both the corrosion rate of the AZ91 alloy, and crack initiation and propagation even in the absence of an external load. Hydrogen absorption leads to a dramatic deterioration in the mechanical properties of the AZ91 alloy, indicating that hydrogen embrittlement is responsible for transgulanar stress corrosion cracking in aqueous solutions.

关 键 词：AZ91 alloy CORROSION HYDROGEN Secondary ion mass spectroscopy （SIMS） Transgulanarstress corrosion cracking （TGSCC） 

分 类 号：TG146.22[一般工业技术—材料科学与工程] TG172[金属学及工艺—金属材料]