Electromagnetic Interference Shielding Effectiveness of Pure SiC-TiSiC Composites Fabricated by Reactive Melt Infiltration.

Silicon carbide-based titanium silicon carbide (SiC-TiSiC) composites with low free alloy content and varying TiSiC contents are fabricated by two-step reactive melt infiltration (RMI) thorough complete reactions between carbon and TiSi alloy in SiC-C preforms obtained. The densities of SiC-C preform are tailored by the carbon morphology and volumetric shrinkage of slurry during the gel-casting process, and pure composites with variable TiSiC volume contents are successfully fabricated with different carbon contents of the preforms. Due to the increased TiSiC content in the obtained composites, both electrical conductivity and electromagnetic interference (EMI) shielding effectiveness improved progressively, while skin depth exhibited decreased consistently.

Influence of Auxiliary Process on Microstructure and Mechanical Properties of Wire Arc Additive Manufacturing of Thick Wall Depositions.

Serious heat accumulation causes poor properties and anisotropy of products in wire and arc additive manufacturing, which restricts the further efficiency in application, especially in double-wire and double-arc depositions. Consequently, this study applied an auxiliary gas process in double-arc additive manufacturing and then compared two 50-layer depositions in morphology, microstructure, and properties to research the influence of the auxiliary process on the forming and performance. The results showed that the auxiliary gas process could improve the deposition morphology, and the efficiency was increased by 24%; moreover, the surface roughness was reduced.

Investigation of the Difference in the Pulse Current in the Double Pulsed Gas Metal Arc Welding of Aluminum Alloys.

In this paper, a double pulse gas metal arc welding (DP-GMAW) for an AA6061-T6 aluminum alloy based on fewer basic welding parameters than the traditional DP-GMAW is proposed. This study compared the difference in pulse base currents (ΔIb) and the difference in the pulse peak currents (ΔIp) by analyzing the electrical signal and morphology properties of welded samples. The results indicated that changing ΔIp caused welding defects or even welding failure easily.