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为从理论上揭示钛金属应力腐蚀行为的本质,建立了α钛晶粒及位错塞积形成的微裂纹原子集团模型,利用递归法(recursion)计算了裂纹及晶粒内的电子结构参量(费米能级、结构能、表面能、团簇能、环境敏感镶嵌能).计算结果表明:氢在裂纹处的环境敏感镶嵌能较低,易于偏聚在裂纹处,且氢在钛金属裂纹处团簇能为正值不能形成团簇,具有有序化倾向,趋于形成氢化物.氢在裂纹处偏聚降低裂纹的表面能,使裂纹容易扩展.裂纹尖端处费米能级高于裂纹其他区域,使电子从裂纹尖端流向裂纹其他区域造成电位差,在电解质作用下裂纹尖端阳极分解腐蚀.
In order to theoretically reveal the nature of the stress corrosion behavior of titanium metal, a group of α-Ti grains and micro-cracks atomic group formed by dislocation buildup were established. The crack and the electronic structure parameters in the grain were calculated by recursion Fermi energy level, structure energy, surface energy, cluster energy and environment-sensitive mosaic energy). The calculated results show that the environment-sensitive mosaic energy of hydrogen at the crack is low and tends to segregate easily at the crack. The clusters can be positive and can not form clusters, with an orderly tendency to tend to form hydrides. Hydrogen segregates at the cracks to reduce the surface energy of the cracks, allowing the cracks to easily expand. The Fermi level at the crack tip is higher In other areas of the crack, electrons flow from the tip of the crack to other areas of the crack causing a potential difference, and the anode of the crack tip decomposes and corrodes under the action of the electrolyte.