氢对不锈钢钝化膜破裂应力的影响

EFFECT OF HYDROGEN ON FRACTURE STRESS OF PASSIVE FILM OF TYPE 316 STAINLESS STEEL

用纳米力学探针测量了316不锈钢电解抛光以及抛光后阳极钝化试样的载荷-压入位移曲线,并研究了氢的影响.结果表明,一旦表面存在氧化膜(电解抛光)或钝化膜(阳极钝化),在载荷-位移曲线上就会出现恒载荷平台;对氧化膜,平台载荷较小,对应膜的屈服;对钝化膜,平台载荷较大,对应膜的破裂.氢可降低钝化膜的平台载荷以及相同载荷下的压入位移,从而使得钝化膜的复合弹性模量Er和破裂应力σF都随试样中氢浓度C0的升高而下降,例如,Er(GPa)=100+82e-0.01Co,σF(GPa)=1.59+2.93 e-0.01C0.

The load-depth curves during nanoindentation into an electropolished or polished and anodic passivation specimens of Type 316 stainless steel were measured. The effect of hydrogen on the load-depth curve and the fracture stress of passive film have been investigated. The results show that the load excursion in the electropolished specimen is ascribed to the onset of plasticity of oxide film formed in air, and that in the passivated specimen ascribed to failure of the passive film. Hydrogen decreased the critical load at the excursion and the depths corresponding to the same loads for the specimen with the passive film. As a result, the reduced Young's modulus E-r and the fracture stress of the passive film sigma(F) decrease with increasing hydrogen concentration C-0, e.g., E-r(GPa)=100+82e(-0.01C0) and sigma(F)(GPa)=1.59+2.93 e(-0.01C0).