Papers by Author: Alokesh Pramanik

Abstract: Silicon-on-sapphire (SOS) thin film systems have had specific electronic applications because they can reduce noise and current leakage in metal oxide semiconductor transistors. However, there are some issues in producing defect-free SOS wafers. Dislocations, misfit, micro twins and residual stresses can emerge during the SOS processing and they will reduce the performance of an SOS product. For some reasons, research publications on SOS in the literature are not extensive, and as a result, the information available in the public domain is fragmentary. This paper aims to review the subject matter in an as complete as possible manner based on the published information about the production, characterization and application of SOS wafers.

Abstract: This paper investigates the effect of tool and workpiece motions on the machining efficiency in the fabrication of hip joint prosthesis. The finite element method was used to characterize the three-dimensional motion of the system, using the uniformity or even distribution of a cutting tool tip trajectory as an efficiency indicator. It was found that a proper combination of the rotational speeds of a cutting tool and a workpiece can improve significantly the efficiency of the machining operation.

Abstract: To produce lifelong, harmless hip joint prostheses, considerable cross-disciplinary studies have been carried out. The research includes adaptability and sustainability of artificial materials to human body, selection of materials, precision fabrication and efficient replacement operation. This paper provides a brief review of some of these key aspects with some details in abrasive polishing.

Abstract: Micro-indentation has been widely used to evaluate the mechanical properties of materials. It has also been considered to be an important measure in the study of machinability of difficult-to-machine materials such as metal matrix composites (MMCs). Because of the complexity of deformation of an MMC and the interaction in the vicinity of contact zone between the indenter and work material, an analytical or experimental method is unable to predict the detailed deformation process. The present paper uses the finite element method to investigate the behavior of MMCs subjected to micro-indentation by a spherical indenter including the development of stress and strain fields in the MMCs during loading/unloading. Particle fracture, debonding and displacement, and inhomogeneous deformation of matrix material were explored and compared with the experimental results reported in the literature. The analysis also provides an insight for understanding the formation of residual stresses in machined MMC components.