The effect of microstructural variations on the fracture toughness of Alloy 718 was reviewed. The metallurgical parameters surveyed in this paper included heat treatment, heat-to-heat variations, product-form variations, neutron irradiation and long-term thermal aging. Key microstructural features and operative fracture mechanisms were related to macroscopic fracture toughness properties.

Cancellous bone microstructure is an important determinant of the mechanical integrity of vertebrae. The numerous microstructural parameters that have been studied extensively are generally represented as a single value obtained as an average over a sample. The range of the intra-sample variability of cancellous microstructure and its effect on the mechanical properties of bone are less well-un...

Conventionally, mean grain size is considered the most critical microstructural parameter in determining the mechanical behavior of pure metals. By systematically controlling the distribution of grain orientations in aluminum films, we show that microstructural heterogeneity alone induces large variation in the mechanical behavior of nanocrystalline metal films. Aluminum films with relatively h...

The impact of La2Zr2O7 !LZO" on interfacial resistance !Rp" at the La0.78Sr0.20MnO3−!/yttria-stabilized zirconia interface was studied upon isothermal sintering at 1200°C for 2–25 h. Quantification of triple phase boundary length was performed by applying focused ion beam/scanning electron microscopy !FIB/SEM" serial-sectioning techniques and classical stereology. Electrochemical impedance spec...

An experimental study is presented on the effect of microstructural change on the Portevin-Le Chatelier effect behaviour of Al-2.5%Mg alloy. Tensile tests are performed on the as received and heat treated (at 400 oC for 16 hours) samples for a wide range of strain rates. The serrations observed in the stress-time curve are investigated from statistical analysis point of view. Microstructures of...

Microstructural effects become important at regions of stress concentrators such as notches, cracks and contact surfaces. A multiscale model is presented that efficiently captures microstructural details at such critical regions. The approach is based on a multiresolution mesh that includes an explicit microstructure representation at critical regions where stresses are localized. At regions fa...

Previous work has demonstrated that injections of the γ-aminobutyric acidA (GABAA) agonist muscimol into the nucleus accumbens shell (AcbSh) induce pronounced increases in the intake of solid foods and sucrose solutions, but do not potentiate water intake. In order to clarify the range of situations in which inactivation of the AcbSh potentiates ingestive behavior, we examined the effects of mu...

The fatigue behavior of the unnotched and notched silicon carbide fiber-reinforced titanium/titanium aluminide hybrid laminated composite was investigated at room temperature. The evolution of microstructural damage and its effect on stiffness and strength degradation was quantified as a function of loading cycles and applied stress levels. Fatigue crack propagation behavior and damage mechanis...

In this work, the mechanical properties and microstructural features of an AISI 304L stainless steel in two presentations, bulk and fibers, were systematically studied in order to establish the relationship among microstructure, mechanical properties, manufacturing process and effect on sample size. The microstructure was analyzed by XRD, SEM and TEM techniques. The strength, Young's modulus an...

A comparative study was carried out for an alloy of Al50(Ni75Mo25)50 processed by two different high energy ball mills. A SPEX and Simoloyer mill were used. The milled products were characterized using X-Ray Diffraction and Scanning Electron Microscopy. A different morphology and microstructural evolution were found with each mill used. It was evident that prolonged milling time induced the for...