Ti_3Al型金属间化合物中氢促进解理断裂的机理

MECHANISM OF HYDROGEN FACILICATED CLEAVAGE IN TITANUM ALUMINIDE

对解理开裂,对氢致解理,氢能促进位错的增殖和运动,从而σ_0(H)<σ_0,k>1,即σ_F(H)<σ_F,K_(IH)<K_(IC)氢通过促进局部塑性变形而促进解理裂纹的形核。

Both hydrogen induced cracking and overload crack initiated at same character-istic distance, r, within the plastic zone along the slip line when the plastic zone developed to a critical extent. For the overload crack:For the hydrogen induced cracking:Hydrogen pomoting the dislocation multiplication and motion would result in σ_o,(H)< σ_o,k> 1. Therefore, hydrogen promoting the cleavage fracture in titanum aluminde can be due to that hydrogen facilicates the local plastic deformation, which results in σ_F(H)< σ_F and then K_(IH)< K_(IC).