Особливості процесу дегазації в α-області системи Pd-H в експериментальній установці для стопу паладій-Гідроґен

The article describes and analyses the changes in the shape of the cantilever made of α-PdHn alloy at a temperature of 240°C with the use of a video recording of the experiment. The experiment is performed for a cantilever made of following alloys: α-PdH0.0105, α-PdH0.0198, α-PdH0.026, α-PdH0.0326, α-PdH0.0464, α-PdH0.0644. The cantilever is covered on one side with a copper film with a thickness of 0.75 μm, which does not allow hydrogen to pass through and does not affect the magnitude of the shape change. Saturation of the palladium cantilever to the α-PdHn alloys is carried out in a chamber at a constant temperature of 240°C. Next, the resulting alloys are kept in isothermal conditions, after which the cantilever is degassed on one side. It is experimentally recorded that, when the pressure changes by ΔРH2 = 0.03, 0.1, 0.15, 0.2, 0.3, 0.43 MPa, the value of the maximum bends for the cantilever increases from -1.6 to -7.05 mm. As established, during the degassing of hydrogen for the cantilever made of α-PdHn alloys, the bend develops in two different time stages. The first stage lasts a very short time (9-15 seconds) and is characterized by the rapid achievement of the maximum bending of the cantilever. The second stage lasts much longer (more than 100 seconds) and is marked by the formation of a plateau and reverse straightening of the cantilever. During the second stage, the cantilever returns to its initial state or reaches a stationary state with minimal deviation from the initial position. As also recorded, the degree of reversibility of cantilever bending during degassing increases with increasing hydrogen pressure. As determined, the internal hydrogen-concentration stresses that arise during degassing of hydrogen from alloys α-PdH0.0105, α-PdH0.0198, α-PdH0.026, α-PdH0.0326, α-PdH0.0464, α-PdH0.0644 exceed the elastic characteristics of gradient alloy α-PdHn (200 MPa) and are in the range from 88 to 539 MPa. The process of formation of the maximum bending of the cantilever in the degassing process for α-PdHn alloys is due to the diffusion transfer of hydrogen, the redistribution of internal stresses in the plate during its bending (straightening) and the corresponding restructuring of the hydrogen-concentration field, which changes the internal conditions of the diffusion transfer of hydrogen into the layers of the α-PdHn alloy. [ABSTRACT FROM AUTHOR]