论文部分内容阅读
Hydrogen-induced cracking (HIC) of two-phase alloy of Ni_3Al+NiAl was in situ investigated using a WOL (wedgeopening-loading) constant deflection specimen in an optical microscopy and using a notched tensile specimen in scan-ning electron microscopy (SEM). Results showed that the threshold stress intensity of HIC was K_(IH)=15.7 MPa·m~(1/2),and (da/dt)Ⅱ=0.019 mm/h. For the uncharged specimen, microcrack initiated and propagated preferentially withinthe NiAl phase, resulting in cleavage fracture, but for the precharged specimen with hydrogen concentration of24.7×10~(-4)%, hydrogen-induced crack initiated and propagated preferentially along the Ni_3Al/NiAl interfaces, result-ing in interphase fracture.
Hydrogen-induced cracking (HIC) of two-phase alloy of Ni_3Al + NiAl was in situ investigated using a WOL (wedgeopening-loading) constant deflection specimen in an optical microscope and using a notched tensile specimen in scan-ning electron microscopy (SEM) . Results showed that the threshold stress intensity of HIC was K IH = 15.7 MPa · m ~ (1/2), and (da / dt) II = 0.019 mm / h. For the uncharged specimen, microcrack initiated and propagated preferentially withinthe NiAl phase, resulting in cleavage fracture, but for the precharged specimen with hydrogen concentration of 24.7 × 10 -4%, hydrogen-induced crack initiated and propagated preferentially along the Ni_3Al / NiAl interfaces, result-ing in interphase fracture .