Process Control by Means of Non Destructive Ultrasonic Testing of Complex W-Cu Contact Components for Energy Transmission and Distribution

Abstract In cooperation with VOGT Ultrasonics GmbH a test stand for non destructive testing of electron beam welded WCu-components and blanks was conceived for testing under serial production conditions by means of the Ultrasonic Phased Array Technology. The early, clear and easy recognition of the quality of the welding zone of WCu welded components with a user friendly Set-Up and software increases the process stability. A fundamental attribute of the ultrasonic test stand is the option to classify the component immediately and online according the defined quality criteria. The challenge amongst high cycle times is to scan powder metallurgical produced WCu composite material components to evaluate the quality of the welding zone underneath. The WCu composite material is usually welded to a homogeneous copper or steel based material. For several reasons it is not possible to send the ultrasonic beam through the homogeneous material in any case. Therefore the measurement has to be carried out through the inhomogeneous WCu part. Herewith the challenge is to avoid a significant ultra sound re-or deflection caused by the microstructure of a WCu composite showing big differences in density, weight and homogenity

Preparing particle reinforced Al-MMCs by mechanical alloying

The properties of particle reinforced metal matrix composites (MMCs) are largely influenced by the homogeneity of the particle distribution. The possibility of the fabrication of MMC powders with a homogeneous particle distribution, a high bulk density and low gas contents by the process of mechanical alloying have been investigated. The milling atmosphere and the type of process control agent have been varied in order to optimize the gas contents and furthermore to take advantage of additional strengthening by oxide or carbide formation. Measurements of the microhardness, the bulk density, the homogeneity of the particle distribution and the gas contents have been done. The progress in reaction milling of graphite has been studied by XRD measurements