Experimental Study of Forming Rene95 Alloy Parts by Laser Cladding

 In this paper, experimental study of forming metal parts by laser cladding Rene95 alloy powder was reported. The influence of main process parameters, such as laser power, scanning speed and laser beam diameter, on the thickness, width and the angle of the laser cladding track was investigated. The microstructures of laser cladding parts were studied and compared with those of common casting parts. The obtained Rene95 metal parts formed by laser cladding are dense and of high strength.
Directed light fabrication of a solid metal hemisphere using 5-axis powder deposition
Abstract Directed light fabrication (DLF) is a direct metal deposition process that fuses metal powders, delivered by gas into the focal zone of a high-powered laser beam, to form a fully-dense metal deposit. Computer-based design and numerical controls are used in conjunction with the metal deposition process to guide the formation of 3D parts. This study demonstrates the ability to directly fabricate complex shapes using a 5-axis DLF machine. As an example, the production of a hemispherical shape is described, with the associated fabrication case study, metallographic examination and part characterization. The deposition of fully-dense stainless-steel components is achieved in all orientations, from horizontal to vertical, and dimensional comparisons between the DLF-deposited shape and the original part definition, illustrates that near-net shape tolerance levels are attainable within a 0.1 mm envelope. The single-step production of fully-dense, near-net shaped, 3D metal parts directly from a computer model is achieved without the use of forming dies, tooling or machining. As a result, significant process flexibility over conventional processing capabilities are recognized, with potentially lower productions costs and higher quality components.
Review of Literature on Probability of Detection for Magnetic Particle Nondestructive Testing
Abstract : A critical review of the available literature concerning the minimum reliably detectable defect size aNDI for magnetic particle testing (MPT) in aerospace applications is presented. Four probability of detection (POD) studies relevant to detection of fatigue cracks in aircraft components were found over the period 1968 to 2011. As the statistical methods used in these four previous studies were either outdated or otherwise deficient, the original data were reanalysed using currently accepted techniques. A meta-analysis of the results is presented, with emphasis on statistical inferences for the defect size expected to be detected with 90% POD. It is shown that the minimum reliably detectable defect size aNDI = 2.0 mm currently specified by the Royal Australian Air Force for wet fluorescent magnetic particle inspection using the continuous method is consistent with estimates of the average performance of MPT derived from the reanalysis of the literature.