Study On The Characteristics Of Hydrogen Retention In Zr-2 Alloy

Zirconium and its alloys have attracted much attention in the field of nuclear power field due to their excellent mechanical properties and strong corrosion resistance.Zirconium alloys are mainly classified into three categories according to their composition:zirconium-tin alloy,zirconium-niobium alloy and zirconium-tin-Niobium alloy.The main reason for the failure of zirconium alloy is the decrease of mechanical properties due to hydride precipitation.Hydrogen is derived from the corrosion reaction between water and metal zirconium.Part of the hydrogen generated in the corrosion reaction adsorbed on the metal surface and then diffused into the matrix.Hydrogen preferentially precipitate along the grain boundary in the form of hydride when reach the limit solid solubility.The research on the types and stability of hydrides in the matrix have also attracted the much attentions.This paper is based on pure zirconium and zirconium-2 alloys.The microstructures of the two materials before and after hydrogenation corrosion were characterized,and the effects of electrochemical hydrogen corrosion time on the hydride species and surface microstructure of the matrix were investigated.The hydrogen micro area corrosion samples were prepared on the surface of pure zirconium by masking,these samples were used to investigate the effect of hydrogenation on the surface spray properties of zirconium.The effects of alloying elements on the retention stability of hydride in zirconium alloy were investigated.The key conclusions of the relevant experiments are obtained,which gives us a new scientific understanding of the stability of hydrides in zirconium alloys and lays the foundation for the following study of the properties of zirconium hydrogen system materials.The researching results can be concisely summarized at the following points:the microstructure of the samples before and after the hydrogenation reaction was carried out by optical microscopy(OM),focused plasma microscopy(FIB),X-ray diffractometry(XRD),thermal desorption(TDS)were applied to analyze the morphology,microstructure,phase composition,and desorption behavior.The surface spray properties of zirconium hydride were studied by Shenguang No.2.The results show that the corrosion time has no significant effect on the hydride species in the metal matrix.Only ? phase hydride is precipitated in the matrix.With the prolongation of the hydrogenation corrosion time,the surface flaking phenomenon is gradually aggravated;Pure zirconium and zirconium-2 alloy were subjected to comparative experiments under the same experimental conditions.It was found that the hydrogen absorption ability of the zirconium-2 alloy was stronger than pure zirconium.At the same time,the hydrogenation layer of the zirconium-2 alloy was thicker under the same conditions.The desorption experiments of the two materials show that the presence of alloying elements reduces the desorption temperature of the hydride in the matrix and reduces the stability of the hydride.A method for hydrogen pitting of metal zirconium surface was prepared to study the surface injection performance of zirconium hydride.The hydrogenation region preferentially breaks and flies out after the shock wave applied,and two different surface ejection ways are observed.