Inter dependence of structure and viscosity of blast furnace slag is discussed based on the available literature. Emphasis is given to both, bridging tendency and network breaking/modifying tendency of the constituents. It is clearly pointed out that slag viscosity cannot be explained only by a process of depolymerisation through an increase of basicity despite the fact that an increase in basicity of the slag, in general, lowers the viscosity of the slag by a process of generation of discrete anions containing simple chains and/or rings by causing depolymerisation of the three dimensional silicate network.

The development of a passive, sonic crystal-based device with unusual properties is reported in this study. This device combines a 1D sonic crystal, a nonlinear medium and an acoustic low-pass filter to allow unidirectional broadband ultrasound propagation as a collimated beam for specialized underwater communication. The signal (220–400 kHz) to be transmitted is first amplitude modulated with a high-frequency ultrasonic carrier wave (2·7–3·25 MHz) and applied to one side of the device. The device then demodulates this signal, and consequently, the original low-frequency signal appears as a collimated beam on the other side. The sonic crystal provides a band-pass acoustic filter through which the high-frequency ultrasonic signal can pass through, and the nonlinear medium then demodulates the signal and also generates the low-frequency sound beam through the parametric array concept. The low-pass filter strips off any remaining high-frequency components and also contributes to the unidirectional property of the device. Design details of the device and experimental data are presented.

In this study, the authors have investigated the properties of GaP_xSb_1–x and InP_xSb_1–x for various structures and compositions using first-principles method. The authors found that GaP_xSb_1–x is less relaxed than InP_xSb_1–x compounds, with respect to their respective binary compounds, due to the larger lattice mismatch. The formation enthalpy decreases from Ga to In compounds and increases with the increasing degree of alloy mixture. The crystal field splitting and band gap are larger in GaP_xSb_1–x than in InP_xSb_1–x. All the properties, investigated in this study, are strongly dependent on structure and composition. Good accord between the calculated results of this study and the experimental values in the literature is obtained.

This article aims to explain why classical thermodynamics is insufficient in macroscopic modeling of solids. Polycrystal grain growth is used as an illustrative example.

Niobium in the form of a ferroniobium alloy is added during the steel-making process to improve the mechanical properties of steel, but it may contain phase(s) with high melting temperatures that may be slow to melt or dissolve. It has been suggested that these phases lead to the presence of coarse Nb-rich particles in the resultant steel, which may adversely affect the mechanical properties. In the present study, electron microscopy and differential scanning calorimetry (DSC) were used to identify phases and microstructural evolution of a commercial grade ferroniobium alloy. The ferroniobium alloy was composed of two main phases, that is, Nb-rich solid solution and μ phase (Fe₇Nb₆). The μ phase (Fe₇Nb₆) was formed as a result of three reactions and exhibited three different morphologies based on their formation temperatures (proeutectic intermetallic, eutectic intermetallic and eutectoid intermetallic). The intermetallic that formed via the eutectic reaction was slightly Nb-rich and was heavily faulted. The Nb-rich eutectic portion of the Fe-Nb binary-phase diagram was also modified based on the DSC results to incorporate the effect of impurities in commercial alloys. On the basis of solidification study, the estimated cooling rate for the as received ferroniobium alloy was 10 K/min.

Primary phase alignment behavior in the Mg-Sb system is explored by solidification of samples in a 35-T DC magnetic field. Compositions with multiple solidification reaction pathways are found to have different phase alignment characteristics. In the current study, the orientation of Mg and Sb primary grains do not appear to be strongly influenced, but the α-Mg₃Sb₂ shows a very strong tendency to align with its long axis perpendicular to the field direction. By comparing the two compositions that both first nucleate α-Mg₃Sb₂ from the melt, it is found that the volume fraction involved in the primary reaction is a controlling factor for the total degree of alignment throughout the structure. This volume fraction dependence is interpreted as hindering free rotation in the liquid.

In this study, the quasi-static deformation and final fracture behavior of Pyrowear 53 is presented and discussed. This novel alloy steel has noticeably improved strength-, ductility- and fatigue-related properties to offer than other competing high-strength alloy steels having near similar chemical composition and processing history. The conjoint influence of composition and secondary processing on intrinsic microstructural effects, stress versus strain response, tensile properties and final fracture behavior are highlighted. The macroscopic fracture mode and microscopic features on the tensile fracture surface are presented and discussed in light of test specimen orientation. The intrinsic microscopic mechanisms governing tensile deformation and final fracture behavior of this novel steel are discussed in light of the role played by intrinsic microstructural features, deformation characteristics of the microstructural constituents and nature of loading.

The sintering temperature plays a major role in determining the microstructural as well as mechanical properties of composite materials. Apart from temperature, there are many factors, such as reinforcement particle geometry and morphology, which directly affect the sintering behavior of the composites. This study emphasizes the role of reinforcement particle geometry in the differential sintering response of copper-alumina composite. The copper and alumina powders were blended, compacted and then sintered conventionally at various temperatures such as 900, 950 and 1000°C. The formation of an interfacial phase has been characterized by X-ray diffraction and scanning electron microscopy. The variations in hardness values were recorded with the variation of sintering temperature, and these have been correlated with the formation of the intermediate compound. The formation of an intermediate phase at 950°C, and the variation in the properties of the composite sketches the profile of interfacial kinetics of the copper-alumina interface when alumina is present as particulate. The decrease in hardness at 950°C indicates the formative stage of CuAlO₂, and then an increase in hardness at 1000°C indicates the strengthening effect of the interfacial compound.

Metallic materials continue to play an essential role as biomaterials to assist with the repair or replacement of various diseased or damaged parts of an anatomy. Currently approved and commonly used metallic biomaterials, such as stainless steel, titanium, cobalt, chromium and other alloys, are found to have adverse effects leading, in some cases, to mechanical failure and rejection of the implant. The physical or chemical nature of the degradation products of some implants initiates an adverse foreign body reaction in tissue. Some metallic implants remain as permanent fixtures, whereas others such as plates, screws and pins that are used to secure serious fractures are removed by a second surgical procedure after the tissue has healed sufficiently. Repeat surgical procedures increase the cost of health care and the possibility of patient morbidity. The concept of magnesium as a biodegradable implant was first investigated 100 years ago by Payr as an innovative approach to address the aforementioned concerns. In this investigation, three alloys were fabricated by casting technology: Magnesium-Zinc (MgZn), Magnesium-Zinc-Calcium (MgZnCa) and Magnesium-Zinc-Calcium-Gadolinium (MgZnCaGd). The alloys were subjected to metallographic characterization by scanning electron microscopy (SEM) and X-ray diffraction (XRD). SEM analysis depicted precipitates; some of which occurred along the grain boundaries, whereas XRD depicted the formation of Laves phases. The mechanical properties and surface energy were also determined. Improved mechanical properties were observed with the addition of alloying elements.