To improve the efficiency of direct laser deposition (DLD) metal powders, a concentrated powder-stream distribution is required, which can be affected by shape powder-delivery nozzle. In this study, simplified, powder particle–wall collision-based 3D numerical model flow in nozzle was used to simulate influences nozzle-exit on concentration stream distribution, characterized its diameter. The p...

The electromagnetic powder deposition (EPD) system employs high velocity gas flow to accelerate powder material to conditions required for high strength plating. The gas flow, however, is not continuous; rather it consists of bursts generated by an electromagnetic railgun and pulsed power system. Each gas burst is created by a high pressure plasma arc which fills a transverse section of the gun...

The Electromagnetic Powder Deposition (EPD) process converts pulsed electrical energy into kinetic and thermal energy to accelerate and heat powder material to conditions suitable for bonding. A high pressure plasma armature is electromagnetically accelerated using a railgun. A supersonic pressure wave is created when the armature accelerates through and "snowplows" the ambient gas ahead of it....

This paper presents a solid freeform fabrication (SFF) technique based on micro-plasma powder deposition (MPPD). The relationship between the geometric features of the deposited layers and the welding parameters is investigated. The arc length is controlled through the monitoring of the arc voltage. The result of building parts with functionally graded components by the MPPD process is shown as...

Lithium-sulfur batteries have attracted attention due to their six-fold specific energy compared with conventional lithium-ion batteries. Dissolution of lithium polysulfides, volume expansion of sulfur and uncontrollable deposition of lithium sulfide are three of the main challenges for this technology. State-of-the-art sulfur cathodes based on metal-oxide nanostructures can suppress the shuttl...

This paper presents a systematic control inputs optimization method for melting interface tracking in laser-aided powder deposition (LAPD) processes. Using a proposed interface approximation and a coordinate system moving with the laser source, and adopting the enhanced thermal conductivity method, the process model is first reduced to a set of coupled partial differential equations (PDEs) in f...

[1] Excavating into the shallow Martian subsurface has the potential to expose stratigraphic layers and mature regolith, which may hold a record of more ancient aqueous interactions than those expected under current Martian surface conditions. During the Spirit rover’s exploration of Gusev crater, rover wheels were used to dig three trenches into the subsurface regolith down to 6–11 cm depth: R...

Laser powder deposition (LPD) has been used for a few decades as a technique that is unique in the application of complex geometry part manufacturing, high-value parts repairing, and surface modification. However, improving the buildup quality of LPD process is still a challenge because of the presence of defects. In this paper, the effect of in-process vibration frequency on the buildup proper...