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计算了有应力和无应力状态下产生非球对称应变的氢原于的化学位之差,μ_σ-μ_0=-VΣσ_iε_(ii)~′,其中U就是氢应变场和外应力场的互作用能.对纯剪应力τ,则U=-0.55133Vτ(ε_(11)-ε_(22)),因而当氢在α-Fe中引起四方畸变时,它和剪应力就有互作用,从而可导致氢在45°面上富集,这就可解释充氢的无裂纹扭转试样以及III型裂纹试样能沿45°面产生氢致滞后断裂的实验事实.当非球对称应变的氢择优分布时,在拉伸和压缩条件下的氢浓度公式并不相同,分别为C_t=C_0exp[(0.70089ε_(11)+0.29911ε_(22))Vo/RT],C_0exp[(0.14956ε_(11)+0.85044ε_(22))Vσ/RT].因此,根据氢渗透实验所获得的C_t/C_0和C_p/C_0,就可定出ε_(11)/ε_(22).例如,用Bockris的数据可得ε_(11)/ε_(22)=1.27.这表明氢在α-Fe中的应变是非球对称的.
We calculate the difference between the chemical positions of the hydrogen atoms that produce aspherical symmetric strain under stress and stress, μ_σ-μ_0 = -VΣσ_iε_ (ii) ~ ’, where U is the interaction energy between hydrogen strain field and external stress field . For pure shear stress τ, then U = -0.55133Vτ (ε_ (11) - ε_ (22)), and thus hydrogen interacts with the shear stress when it causes tetragonal distortion in α-Fe, Hydrogen enrichment at a 45 ° surface can explain the experimental fact that hydrogen-filled crack-free torsional specimens and type III crack specimens can produce hydrogen-induced hysteresis fracture along the 45 ° surface. When the hydrogen preferential distribution of aspheric strain , The formula of hydrogen concentration under the conditions of stretching and compressing are not the same, which are C_t = C_0exp [(0.70089ε_ (11) +0.29911ε_ (22)) Vo / RT] and C_0exp [(0.14956ε_ (11) + (11) / (22) can be determined from the C_t / C_0 and C_p / C_0 obtained from the hydrogen permeation experiments.For example, data available from Bockris ε 11 / ε 22 = 1.27 This shows that the strain of hydrogen in α-Fe is aspherical symmetric.