Fracturing and Deformation Characteristics of Aluminium Preform during Cold Forging at Low Strain Rates
The industrial processing of sintered powder preform has been developed for manufacturing various engineering components. The present investigation has been undertaken to analyze the deformation characteristics during the cold forging of sintered aluminium preform at low strain rates. Experiments have been conducted and measurements made on deformation during cold forging on aluminium preforms with lubricated end conditions. Experimentally obtained flow load and plastic work done are in good agreement with theoretical estimates.
An investigation on the workability of sintered copper-silicon carbide preforms during cold axial upsetting
An investigation has been carried out for the determination of the workability behaviour of Cu-SiC composites under two different stress conditions namely plane and tri-axial state. Cylindrical preforms with 95% initial preform density possessing aspect ratio of 0.60 are prepared from copper with various percent content of silicon carbide (up to 20%) metal matrix composites using a die and punch assembly with a 1.0 MN capacity Universal Testing Machine. The sintering operation is carried out in an electric furnace at 850 ± 10°C for a period of one hour in argon inert atmosphere and subsequently they are furnace cooled. Each sintered preform is subjected to an incremental compressive loading under zinc stearate as lubricant. Based on the experimental results, the phenomenon like axial strain (εz), various stress ratio parameters (namely (σm/σeff) and (σθ/σeff)) and the formability stress index (β) under two different stress state conditions are systematically analysed considering the barreling effects.
Physical Ageing of the Research Reactor Core Structural Materials Due to Neutron Irradiation Exposure: a Review
A research reactor (RR) is a  nuclear reactor that has function to generate and utilize neutron flux and radiation ionization for  research purposes and industrial applications. More than 60% of current operating RRs have  been operated for 30 years or more. As the time passes, the functional capabilities of structures,  systems and components (SSCs) of those RRs deteriorate by physical ageing, which can be  caused by neutron irradiation exposure such as irradiation induced dislocation and  microstructural changes. To extend the lifetime and/or to avoid unplanned outages, ageing on  the safety related SSCs of RRs need to be properly managed. An ageing management is a  strategy to engineer, operate, maintenance, and control SSC degradation within acceptable limits. The purpose of this study is to review physical ageing of the core structural materials of  the RRs caused by neutron irradiation exposure. In order to achieve this objective, a wide range  of literatures are reviewed. Comprehensive discussions on irradiation behaviors are limited only  on reactor vessel and core support structure materials made from zirconium and beryllium as  well as their alloys, which are widely used in RRs. It is found that the stability of the mechanical  properties of zirconium and beryllium as well as their alloys was mostly affected by the neutron  fluences and temperatures.