Manufacturing of W/steel composites using electro-discharge sintering process

Tungsten-steel metal matrix composites are consolidated using electro-discharge sintering. At first steel and tungsten powders are sintered separately and then 25 vol% W, 50 vol% W and 75 vol% W mixed powders are sintered. A thorough process parametric study is carried out involving analysis of the influence of particle size distribution, sintering pressure, and discharge energy on the maximum discharge current and obtained residual porosity. Thermal expansion coefficient and the specific heat capacity of the optimized sintered composites are almost same as their theoretical values, however the thermal conductivities and the mechanical properties are lower than the expected values

Densification of NdFeB magnets by electro-discharge sintering - Microstructure, mechanical and magnetic properties

In this work, the densification process of nanocrystalline NdFeB powder by electro-discharge sintering (EDS) was investigated. The EDS technique is used as a fast and energy-saving compaction process for metal powders. In contrast to the spark plasma sintering (SPS) process, EDS has not received much attention during recent years. SPS is a low voltage, direct current, pulsed current-activated, and pressure-assisted sintering process. Whereas EDS is also pressure-assisted, but uses electrical energy discharged from capacitors to densify conductive powders. During EDS a large current is discharged within 5 ms from capacitors into a pre-compacted loose powder, thus resulting in complete compaction. Please click Additional Files below to see the full abstract

Electro-discharge sintering of nanocrystalline NdFeB magnets

This study investigates the compaction of nanocrystalline NdFeB magnet powder by electro-discharge sintering (EDS). On this account, process parameters, microstructure, and the associated magnetic properties of the EDS-densified nanocrystalline NdFeB specimens were investigated by varying the discharge energy $E_{EDS}$ and compression load $\it {p}_{EDS}$. Although optimized process parameters could be evaluated, three different microstructures (fully densified zone, insufficiently densified zone, and melted zone) are present in the EDS-compacted specimens. Thereby, volume fractions of these formed three different microstructures determine the resulting mechanical and magnetic properties of the specimens. For all specimens, the intrinsic coercivity $H_{c,J}$ deteriorates with increasing discharge energy, as the generated Joule heat leads to microstructural changes (grain growth, dissolution of magnetic phases), which reduces the magnetic properties. The compression load has less influence on the coercivity $H_{c,J}$, as it only affects the initial resistance of the pre-compacted powder loose. The residual induction $B_{r}$ deteriorates with increasing the discharge energy due to microstructural changes. An increase in the compression load $\it {p}_{EDS}$ results in an increase in the specimens' density and thus promotes the residual induction $B_{r}$

Study of lanthanum aluminum silicate glasses for passive and active optical fibers

International audienc

CTA Contributions to the 34th International Cosmic Ray Conference (ICRC2015)

List of contributions from the CTA Consortium presented at the 34th International Cosmic Ray Conference, 30 July - 6 August 2015, The Hague, The Netherlands.Comment: Index of CTA conference proceedings at the ICRC2015, The Hague (The Netherlands). v1: placeholder with no arXiv links yet, to be replaced once individual contributions have been all submitted; v2: final with arXiv links to all CTA contributions and full author lis

CTA contributions to the 33rd International Cosmic Ray Conference (ICRC2013)

Compilation of CTA contributions to the proceedings of the 33rd International Cosmic Ray Conference (ICRC2013), which took place in 2-9 July, 2013, in Rio de Janeiro, BrazilComment: Index of CTA conference proceedings at the ICRC2013, Rio de Janeiro (Brazil). v1: placeholder with no arXiv links yet, to be replaced once individual contributions have been all submitted. v2: final with arXiv links to all CTA contributions and full author lis