Elevated temperature tensile properties of powder metallurgy Ni3Al alloyed with chromium and zirconium

The tensile properties of hot extruded powders of Ni-24.1Al, Ni-19.1Al-8.5Cr, and Ni-17.4Al-7.9Cr-0.5Zr have been evaluated from room temperature to 1000° C. These powder metallurgy materials have a fine grain size that results in relatively little increase in yield stress with increasing temperature compared to coarse-grained or single-crystal materials. The alloy containing chromium and zirconium shows greatly reduced dynamic embrittlement in the temperature range 600 to 800° C where the unalloyed aluminide exhibits brittle behaviour. The Cr- and Cr + Zr-containing alloys deform superplastically above 900° C. The mechanism of superplastic deformation appears to be predominantly grain-boundary sliding.     

Correlation-based interferometric method of evaluating the beat length

A new, to our knowledge, interferometric method of measuring beatlengths in polarization-maintaining fibers that is based on correlationmeasurements is presented.     

Effect of Al substitution and secondary CuO phase on dielectric response in microwave-processed CaCu3Ti4−xAlxO12 ceramics

Journal of Materials Science: Materials in Electronics - High dielectric loss is a major drawback in CCTO-based electroceramics, and such high dielectric loss supports good microwave coupling for...     

Scientific Perceptions and Community Responses in a Participatory Water Management Endeavor

People and technology are the two major ingredients considered to enhance benefits and provide opportunities in farming system. Perfect blending of these ingredients not only leads to maximize the agricultural production but also helps in improving livelihood. Openhanded efforts have been initiated to understand farm resources, production constraints and support services in order to suggest need based and cost effective technologies/practices, which can be adopted by the farmers employing participatory approach without or least financial incentivization. This approach is in contrast to earlier approaches where quality inputs and incentives are provided by project implementing agencies to promote technologies/practices. As in the earlier approach the farmer’s involvement in planning and implementation is poor, introduction of participatory process and technologies/practices remains no longer sustainable and once the financial support from the project area is withdrawn farmers’ follow the same age old traditional practices. This led to realization that perspectives of local people’s needs to be in the center of development, research and extension efforts, if substantial impact is to be made. The objective of this paper is to share the experiences of a multi disciplinary and multi institutional participatory approach undertaken, in ICAR-DFID collaborative project in India, to improve livelihood of community including poorest of the poor through integrated land and water management. The purpose here is to establish a more differentiated communication and a conceptual framework, which can help researchers and practitioners to make better choices and more informed decisions when designing their research, communication and dissemination approaches.     

Cavitation erosion of NiAl

Vibratory cavitation erosion tests were carried out on as-cast NiAl intermetallic compounds containing 46.5 to 62.1 at pct Ni. The erosion rate decreased with increasing nickel content by over two orders of magnitude, from a high of 16.4 to 0.11 mg·h⁻¹. These low erosion rates exhibited by the nickel-rich alloys containing 58 and 62.1 at. pct Ni, the interruptions in their mass loss with time, and the unusual effects associated with surface finish and intensity of cavitation were found to be associated with the stress-induced martensitic transformation. Alloys containing 58 to 62 at. pct Ni have the potential for use as materials for the cavitation protection of hydraulic machinery.     

Experiments on low velocity cooling of high conductivity substrates

Experiments are reported on low velocity cooling of a heater-on-substrate geometry for high conductivity substrate materials. Four different substrate materials were studied: 1) aluminum 6061-T6; 2) aluminum nitride; 3) alumina; 4) FR-4. The effects of combined buoyancy and forced air flow, geometric orientation, substrate size, thermal conductivity, and emittance on heat transfer are evaluated. Results define the performance of the substrates and the limits of conjugate mixed convection for horizontal substrates, and of orientation effects for substrates tilted from buoyancy-opposing to buoyancy-assisting orientations. An analytical approximation is described that predicts the experimental data with good accuracy over broad parameter ranges