Fracture Toughness of Cold Sprayed Pure Metals

The study of fracture toughness of pure Al, Cu, Ni and Ti deposited by cold spray was performed in order to obtain a fundamental understanding of the damage process and quantify the material performance. Rectangular specimens cut from self-standing deposits with fatigue pre-cracks were tested in three-point bending. The KIC values were obtained from J-R curves following the ASTM E1820 standard. The stress–strain behavior of the tested material was obtained from supplementary four-point bending. The cold spray deposits exhibited significantly lower fracture toughness than the corresponding wrought materials. The reduction was more pronounced for coatings with limited ductility (Ti and Cu), where the fracture toughness reached less than 12% of the wrought counterpart only. The higher ductility coatings of Al and Ni possessed fracture toughness of 18–25% of the wrought reference materials. The performed fractographic analysis revealed inter-particular decohesion as the major failure mode

Plasma spray synthesis of nanozirconia powder

Abstract not available

In-Flight Particle Diagnostic of Water Stabilized Plasma Spray Process

Peer reviewed: YesNRC publication: Ye

Plasma spraying of a novel material with amorphous and nanocrystalline microstructure

A novel material has been used for plasma spraying by WSP\uae. The material is composed of three main phases, namely corundum (aluminum oxide), baddeleyite (zirconium oxide), and glassy phase (silicon oxide). The material is a refractory and exhibits very high hardness, extremely high abrasion resistance, and chemical resistance. Conventionally, the material is fabricated by melt casting and machining. Cast tiles of the material were ground and sieved to obtain the right powder cut size for plasma spraying by water stabilized plasma torch (WSP\uae). Both dense coatings and free standing parts were successfully produced from the new material by WSP\uae. Spraying parameters were varied and molten particles were monitored in flight by DPV 2000. The coatings exhibit very low porosity and high hardness. The as-sprayed material is mostly amorphous with some nanocrystalline grains of aluminum and zirconium oxide present. The phase composition of the as-sprayed material is thus different from that of the feedstock material, which is mostly crystalline with a small faction of amorphous silica glass. The micro-structure of the newly sprayed material was studied by electron microscopy (SEM, TEM) and is very complex. Upon annealing, the as-sprayed material crystallizes around 950\ub0C. This result and other thermal properties were obtained by TMA and DTA measurement. The ease of plasma spraying and the coating properties make this material a suitable candidate for many industrial applications.Peer reviewed: NoNRC publication: Ye

Special magnetic Co-Fe-Nb alloys II; precipitation and selected properties

15.00; Translated from Czech. (Kovove Mater. 1987 v. 25(1) p. 69-80)Available from British Library Document Supply Centre- DSC:9023.19(VR-Trans--3846)T / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo

The Effect of High Flux H Plasma Exposure with Simultaneous Transient Heat Loads on Tungsten Surface Damage and Power Handling

The performance of the full-W ITER divertor may be significantly affected by the interplay between steady-state plasma exposureand transient events. To address this issue, the effect of a high-flux H plasma on the thermal shock response of W to ELM-liketransients has been investigated. Transient heating of W targets is performed by means of a high-power Nd:YAG laser withsimultaneous exposure to H plasma in the linear device Magnum-PSI. The effects of simultaneous exposure to laser and plasmahave been compared to those sequentially and to laser only. Transient melting is found to be aggravated during plasma exposureand to occur at lower heat flux parameters. Roughness and grain growth are observed to be driven by peak temperature, ratherthan by the loading conditions. The temperature evolution of the W surface under a series of transients is recorded by fastinfrared thermography. By accounting for changes in the reflectivity at the damaged surface as measured by ellipsometry, areduction in power handling capabilities of the laser/plasma affectedWis concluded. The evidence of reduced power handlingof theWsurface under conditions as described here is of great concern with respect to the durability ofWPFCs for applicationin fusion devices