Hong LU
,
Kewei GAO
,
Hui LIU
,
Lijie QIAO
,
Wuyang CHU
材料科学技术（英文）
alpha -Ti foil with a protective layer formed on one side was deflected during corrosion in a methanol solution containing 0.6 mol/L KCl and then a tensile stress was generated at or near the metal passive film interface. The in situ TEM observation showed that corrosion process could facilitate dislocation emission and motion. Adding 10% H2O into the methanol solution decreased the passive film-induced stress from 320 MPa to zero, and the susceptibility to SCC measured in slow strain rate tests decreased correspondingly from 98% to zero.
关键词:
Chuan PAN
,
Zhengbang LI
,
Zhiling TIAN
,
Dongtu LIANG
,
Lijie QIAO
,
Wuyang CHU
材料科学技术（英文）
For 308L and 347L weld metals of austenitc stainless steels (ASS), hydrogen induced cracking (HIC) occurred during dynamically charging under constant load. The threshold stress intensity for HIC, KIH, decreased linearly with the logarithm of the concentration of diffusible hydrogen C0 in the weld metals and the rolled plate of type 304L ASS, i.e., KIH=85.2-10.7ln C0 (308L),KIH=76.1-9.3ln C0(347L), and KIH=91.7-10.1ln C0(304L). The fracture mode for HIC in the three type of ASS changed from ductile to brittle with the decrease in the applied stress intensity KI or/and the increase in C0. The boundary line between ductile and brittle fracture surfaces was KI-54+25exp(-C 0/153)=0.
关键词:
Austenitic stainless steel
,
null
,
null
Jinxu LI
,
Yanbin WANG
,
Lijie QIAO
,
Wuyang CHU
材料科学技术（英文）
Hydrogen-induced cracking (HIC) of two-phase alloy of Ni3Al+NiAl was in situ investigated using a WOL (wedge opening-loading) constant deflection specimen in an optical microscopy and using a notched tensile specimen in scanning electron microscopy (SEM). Results showed that the threshold stress intensity of HIC was KIH=15.7 MPa·m1/2, and (da/dt)II=0.019 mm/h. For the uncharged specimen, microcrack initiated and propagated preferentially within the 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 Ni3Al/NiAl interfaces, resulting in interphase fracture.
关键词:
Ni3Al+NiAl
,
null
,
null
,
null
Hongqi LI
,
Yanbin WANG
,
Wuyang CHU
材料科学技术（英文）
Using a special constant deflection device, the changes in dislocation configuration ahead of a loaded crack tip for 60Fe40Ni alloy, before and after magnetization in a magnetic field, have been studied in TEM. The results showed that the magnetization for 60Fe40Ni alloy could enhance dislocation emission, multiplication and motion. Also, the mechanical properties of 60Fe40Ni alloy, in air and in the magnetic field respectively, have been investigated using the slow strain rate tension. And the results indicated that magnetization could make the yield strength corresponding to decrease by 26 percent, but did not influence the ultimate tensile strength and the fracture strain, which showed that magnetization could enhance plastic deformation.
关键词:
