高压氢气对金属材料断裂韧性的影响

Effect of High-Pressure Hydrogen Gas on Fracture Toughness of Metals

基于应力诱导氢扩散理论、氢致键合力降低理论和线弹性断裂力学理论,提出了一个描述氢气对金属断裂韧性影响的数学模型,用于定量预测金属在氢气中的断裂韧性.结果表明,当已知金属在低压氢气中的断裂韧性时,利用所提出的模型可以外推出金属在高压氢气中的断裂韧性,从而避免了在高压氢气中测量金属断裂韧性所带来的危险性.同时,利用文献报道的几种金属材料在不同氢气压力下的断裂韧性试验值对模型进行验证发现,所建立的模型对预测金属在氢气中的断裂韧性具有较好的有效性.

Fracture toughness is an important property to characterize the resistance of metals against crack initiation and growth. It has been found that hydrogen gas has a detrimental effect on fracture toughness of many metals. It is a very difficult and dangerous task to measure experimentally the fracture toughness of metals in hydrogen gas, particularly in high-pressure hydrogen gas. In this paper, a model was developed to quantify the effect of hydrogen on the fracture toughness of metals based on the theories of stress-in duced hydrogen diffusion, hydrogen enhanced decohesion and fracture mechanics. Experimental data in some literatures were used to verify the model, and a good agreement was obtained. The model can be used to predict fracture toughness of metals in hydrogen gas, or to extrapolate the fracture toughness of steels in the high pressure hydrogen gas based on the fracture toughness obtained experimentally in the low pres sure hydrogen gas.