Beryllium copper/palladium alloy electron beam welded sliding contacts
The advantages and process limitations of the latest generation of electron-beam-welded materials are reviewed. The study of metallurgical properties in the weld zone utilizes scanning electron microscopy and metallographic techniques. Various material and weld parameters are evaluated at they relate to final mechanical properties. The relationships of design criteria to metallurgical characteristics and to the effects of heat treatment are discussed.<<ETX>>
Electron-Beam Technology in Switch Contacts
The original concept was to develop a composite strip of material for switch contacts, such that the silver portion is suitably bonded to the base metal such as copper, phosphor bronze, or beryllium copper. The requirements were a metallurgically sound reproducible-nonporous uniform ductile bond. Electron-beam welding technology meets these requirements for joining switch contact materials. Fine silver, coin silver, silver cadmium oxide, and other wrought contact materials can be continuously electron-beam welded to the base metal switchblade member and then subsequently stamped and formed to the necessary switch configuration. This manufacturing technique is an improvement over the alternate joining methods of resistance welding, brazing, tungsten inert gas welding, thermocompression bonding, and the more recent laser welding.
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.