Advanced resonant ultrasound spectroscopy for measuring anisotropic elastic constants of thin films

This paper presents an advanced resonant ultrasound spectroscopy (RUS) method to determine the elastic constants C_ij of thin films. Polycrystalline thin films often exhibit elastic anisotropy between the film growth direction and the in‐plane direction, and they macroscopically show five independent elastic constants. Because all of the C_ij of a deposited thin film affect the mechanical resonance frequencies of the film/substrate layer specimen, measuring resonance frequencies enables one to determine the C_ij of the film with known density, dimensions and the C_ij of the substrate. Resonance frequencies have to be measured accurately because of low sensitivity of the C_ij of films to them. We achieved this by a piezoelectric tripod. Mode identification has to be made unambiguously. We made this measuring displacement–amplitude distributions on the resonated specimen surface by laser Doppler interferometry. We applied our technique to copper thin film and diamond thin film. They show elastic anisotropy and the C_ij smaller than bulk values of C_ij. Micromechanics calculations indicate the presence of incohesive bonded regions.     

Electrical Conduction in Sintered α-Sb2O4

Electrical conductivity and thermoelectric power were measured on sintered α-Sb₂O₄ at 250° to 780°C. Oxygen partial pressure dependence of the conductivity and sign of the Seebeck coefficient showed α-Sb₂O₄ to be a p -type semiconductor above 600°C in the oxygen pressure range of lo⁵ to 10² Pa. A hopping conduction was proposed from very small hole mobility with an activation energy of 18 kJ/mol.     

A probabilistic approach for thermal shock fatigue life of glass

This paper presents a probabilistic approach for predicting fatigue life of glass subjected to near‐ΔT_C (critical temperature difference) thermal shock which exhibits little subcritical crack extension. First, thermal shock fatigue life N_f was derived as a function of temperature difference ΔT, fracture probability F and Biot's modulus β from the slow crack growth concept in conjunction with the Weibull distribution model. Next, thermal shock fatigue tests as well as flexural tests were performed for borosilicate glass to measure ΔT_C and N_f versus ΔT. The parameters associated with slow crack growth were then determined from the experimental results while the heat transfer coefficient h or β was obtained with the aid of finite element analysis. Thirdly, the thermal shock fatigue diagram (ΔT?N_f curves) was depicted for various values of β. Finally, crack length was simulated on the basis of the present approach.     

高碳高钒高速钢的高温硬度及热处理的研究

研究了高碳高钒高速钢的淬火、回火热处理及高温硬度。结果表明,其峰值硬度温度较常规高速钢低１５０～２５０℃左右,随碳量增加,峰值硬度温度降低,相同碳量、钡量增加,峰值硬温度升高。回火后的硬度变化和常规高速钢呈相同的趋势,次硬化温度约在５５０℃,但二次硬化的峰值硬度峰较小,在二次硬化温度二次回火,二次硬化作用消失。随碳量、钒量增加,高温硬度增加。根据轧辊辊面硬度要求,高碳高钒高速钢的淬火温度为９５０～     

含硅量和冷却速度对中铬铸铁碳化物的影响

对金属型和砂型铸造的含硅量不同的2．79％C-7.17％Cr-0.48％Mn中铬铸铁试样进行了显微组织研究和热分析,结果表明：(Fe,Cr)7C3碳化物量随含硅量的增加和冷却速度的降低而增加。因此,为了增加中铬铸铁显微组织中(Fe,Cr)7C3碳化物的量,应增加化学成分中硅的含量,并控制和降低冷却速度。     

Suppression of ignition and burning of molten Mg alloys by Ca bearing stable oxide film

Abstracts are not published in this journal This revised version was published online in November 2006 with corrections to the Cover Date.