Study On The Interaction Effect Of Titanium Alloy Crack Tip Mechanics And Hydrogen Diffusion In Marine Corrosion Environment

Due to its good mechanical properties and excellent corrosion resistance,titanium alloy materials are known as the most promising new metal materials in the future,so they are widely used in aircraft,ships,industrial production and other fields.Titanium alloy materials serving in the marine environment are prone to corrosion and hydrogen embrittlement under the action of complex working conditions such as corrosive media and external stress for a long time,resulting in failure of component materials and irreversible economic losses.This paper takes titanium alloy materials as the research object,and establishes a model of titanium alloy crack tip mechanics,crack tip hydrogen diffusion and crevice electrochemical corrosion environment coupled with crack tip hydrogen diffusion model,and analyzes the interaction between mechanics and electrochemical environment.Distribution law of electrochemical parameters such as ion concentration in the field and crack crevice.The main research contents of this paper are as follows:(1)Based on Fick’s second law and the theory of hydrogen-influenced plastic deformation,a mathematical model of the interaction between crack tip mechanics and hydrogen diffusion of titanium alloys was established;the finite element calculation model of crack tip mechanics and hydrogen diffusion was established in COMSOL software,using To study the influencing factors of hydrogen diffusion at the crack tip of titanium alloys and the influence factors of hydrogen on the mechanical properties of materials;through the study,the influence of material properties,applied loads,service temperature and crack depth on hydrogen diffusion and the influence of hydrogen on the mechanical properties of materials are obtained.(2)According to the principle of crevice electrochemical corrosion,establish a mathematical model of crevice electrochemical corrosion of titanium alloys;establish a finite element model of crevice electrochemical corrosion according to the mathematical model,and analyze the distribution of electrochemical parameters and ion concentrations in the electrolyte solution of cracks and crevices;The effects of reaction time,gap depth and applied potential on the electrochemical parameters and ion concentration distribution in the crack gap are obtained.(3)In the COMSOL software,the mechanical field of the crack tip,the hydrogen diffusion at the crack tip and the electrochemical corrosion environment are coupled,and the coupling model of the titanium alloy crack tip mechanics and hydrogen diffusion in the corrosive environment is established to study the titanium alloy crack tip in the seawater corrosion environment.The relationship between mechanics and hydrogen diffusion was obtained,and the effects of applied load,reaction time,and different permeation ratios on the hydrogen concentration distribution were obtained.