A new method for determining the fractal dimension by STM at nanomeler scale has been proposed.Widerstrass- Mandelbrot fractal curves were used to verify the accuracy and reliability. The Computer simulation showed th...A new method for determining the fractal dimension by STM at nanomeler scale has been proposed.Widerstrass- Mandelbrot fractal curves were used to verify the accuracy and reliability. The Computer simulation showed that fractal dimen- sion obtained with this method generally outran the traditional yard method. The new method has been applied to the fractal dimension determination of the fractures of Ti3Al and Ti-24Al-11Nb alloys. The results show that the fractal dimension of Ti-24Al-11Nb alloy is higher than that of Ti3Al, and it varies with the crark extending orientation.展开更多
This review is about stress corrosion cracking (SCC) under anodic dissolution control. The section 1 is the methods distinguishing SCC controlled by anodic dissolution from those by hydrogen. The section 2 presents hy...This review is about stress corrosion cracking (SCC) under anodic dissolution control. The section 1 is the methods distinguishing SCC controlled by anodic dissolution from those by hydrogen. The section 2 presents hydrogen-enhanced corrosion and SCC under anodic dissolution control. The section 3 demonstrates corrosion-enhanced localized plasticity and corrosion-induced deformation localization, which are the fundaments of new mechanism of SCC. The section 4 is an overview of the proposed mechanisms of SCC under anodic dissolution control. The last section proposes a new mechanism of SCC.展开更多
Stress corrosion cracking (SCC) of a PZT ferroelectric ceramics in various media, such as moist at-mosphere, silicon oil, methanol, water and formamide, and its anisotropy have been investigated at constant load test ...Stress corrosion cracking (SCC) of a PZT ferroelectric ceramics in various media, such as moist at-mosphere, silicon oil, methanol, water and formamide, and its anisotropy have been investigated at constant load test using a single-edge notched tensile specimen. The results showed that SCC could occur in all media, and the threshold stress intensity factor of SCC in water and formamide, KISCC, revealed anisotropy. The KISCC for poling direction parallel to the crack plane, aISCC,Kwas greater than that perpendicular to the crack plane, bISCC,K similar to the anisotropy of fracture toughness KIC; however, the anisotropy factor of KISCC, which was abISCCISCC/KK=1.8 (in formamide) and 2.1 (in water), was larger than that of KIC, which is abICIC/KK=1.4. The stress-induced 90?domain switching causes the anisotropy of KIC and KISCC, besides, the resistance of SCC also has anisotropy.展开更多
文摘A new method for determining the fractal dimension by STM at nanomeler scale has been proposed.Widerstrass- Mandelbrot fractal curves were used to verify the accuracy and reliability. The Computer simulation showed that fractal dimen- sion obtained with this method generally outran the traditional yard method. The new method has been applied to the fractal dimension determination of the fractures of Ti3Al and Ti-24Al-11Nb alloys. The results show that the fractal dimension of Ti-24Al-11Nb alloy is higher than that of Ti3Al, and it varies with the crark extending orientation.
基金This work was supported by a special fund forIhe Major State Basic Research Projects (Grant No. G19990650) and the National Natural Science Foundation of China (Grant Nos. 19891180 and 59871010).
文摘This review is about stress corrosion cracking (SCC) under anodic dissolution control. The section 1 is the methods distinguishing SCC controlled by anodic dissolution from those by hydrogen. The section 2 presents hydrogen-enhanced corrosion and SCC under anodic dissolution control. The section 3 demonstrates corrosion-enhanced localized plasticity and corrosion-induced deformation localization, which are the fundaments of new mechanism of SCC. The section 4 is an overview of the proposed mechanisms of SCC under anodic dissolution control. The last section proposes a new mechanism of SCC.
文摘Stress corrosion cracking (SCC) of a PZT ferroelectric ceramics in various media, such as moist at-mosphere, silicon oil, methanol, water and formamide, and its anisotropy have been investigated at constant load test using a single-edge notched tensile specimen. The results showed that SCC could occur in all media, and the threshold stress intensity factor of SCC in water and formamide, KISCC, revealed anisotropy. The KISCC for poling direction parallel to the crack plane, aISCC,Kwas greater than that perpendicular to the crack plane, bISCC,K similar to the anisotropy of fracture toughness KIC; however, the anisotropy factor of KISCC, which was abISCCISCC/KK=1.8 (in formamide) and 2.1 (in water), was larger than that of KIC, which is abICIC/KK=1.4. The stress-induced 90?domain switching causes the anisotropy of KIC and KISCC, besides, the resistance of SCC also has anisotropy.
