The effect of Si doping on the strain and microstructure in GaN films grown on sapphire by metalorganic chemical vapor deposition was investigated. Strain was measured quantitatively by x-ray diffraction, Raman spectroscopy, and wafer curvature techniques. It was found that for a Si concentration of 2310 cm, the threshold for crack formation during film growth was 2.0 mm. Transmission electron ...

This paper describes a web-based finite element program called portal of damage. The purpose of the program is the numerical simulation of reinforced concrete framed structures, typically buildings, under earthquakes or others exceptional overloads. The program has so far only one finite element based on lumped damage mechanics. This is a theory that combines fracture mechanics, damage mechanic...

A non-destructive thermographic methodology based on the temperature field is utilized to determine crack tip position during very high cycle fatigue (VHCF) test of pure iron and deduce corresponding growth rate (FCGR). To this end, a piezoelectric machine employed 1 mm thick samples at 20 kHz in push–pull loading. Two cameras are placed each side plate sample, an infrared one for measuring fie...

(This is part 2, continued from “Use of harsh Wafer Probing to Evaluate Traditional Bond Pad Structures”). Goals for circuit under pad (CUP) in aluminum – silicon dioxide (Al – SiO2) based IC pad structures include the design of metal interconnects in all layers beneath the pad Al, and the ability to withstand harsh probing and wirebonding stress without SiO2 cracking, without deforming or bend...

J. Kasińska, Faculty of Mechatronics and Machine Design, Kielce University of Technology, Kielce, Poland This paper presents influence of rare earth metals (REM) on the mechanical properties, microstructure and morphology of non metallic inclusions as well as the cracking mechanism of G17CrMo5-5 high temperature cast steel. The research has been performed on successive industrial melts. It was ...

Effect of Cracks on Elastic Properties of Low Porosity Rocks by Terrence Patrick Todd Submitted to the Department of Earth and Planetary Sciences on May 1, 1973, in partial fulfillment of the requirements for the degree of Doctor of Philosophy Microcracks in terrestrial and lunar rocks significantly alter elastic, thermal, and mechanical properties. The degree to which microcracks alter physica...

The potentiodynamic polarization test and slow strain rate tensile tests of X80 pipeline steel were performed in 0.5M Na2CO3-1M NaHCO3 solution to study the electrochemical and stress corrosion cracking properties. The results of potentiodynamic polarization test show that there is an obvious stable passive region, about from 0v to 0.8V (SCE), indicating that anodic protection is feasible. The ...

Abstract Nearly all commercially available alloys have been developed for manufacturing processes other than additive manufacturing. Most of those are not suitable laser powder bed fusion (L-PBF) processing due to the non-weldable nature casting, forging, and machining. Even some weldable can be difficult produce with L-PBF because characteristics L-PBF, such as highly concentrated heat input e...

Brillouin light scattering measurements have been used to study the stress induced modification in the elastic properties of two glass forming polymers: polybutadiene and epoxy-amine resin, prototypes of linear and network polymers, respectively. Following the usual thermodynamic path to the glass transition, polybutadiene has been studied as a function of temperature from the liquid well into ...

The abrupt change in material properties across the interface between different materials can result in large inter-laminar stresses leading to delimitation, cracking, and other damage mechanisms which result from the abrupt change of the mechanical properties at the interface between the layers. Initially the uncertainty in material properties at micro level is finally reflected as macro level...