Defect structures in MgB₂wires introduced by hot isostatic pressing

Abstract

The microstructures of MgB 2 wires prepared by the powder-in-tube technique and subsequent hot isostatic pressing were investigated using transmission electron microscopy. Large amount of crystalline defects including small angle twisting, tilting, and bending boundaries, in which high densities of dislocations reside, were found forming sub-grains within MgB 2 grains. It is believed that these defects resulted from particle deformation during the hot isostatic pressing process and are effective flux pinning centers that contribute to the high critical current densities of the wires at high temperatures and at high fields.

Synthesis of dense bulk MgB2by an infiltration and growth process

“…There have been numerous reports of the synthesis of bulk MgB 2 via sintering, and a number of studies have shown that high pressure and elevated temperature [15,16] are effective in promoting MgB 2 phase formation and subsequent sintering. The use of high-pressure leads typically to the introduction of defects in the MgB 2 structure that form effective pinning centres [17].…”

Elastic deformation behavior and microstructure evolution of single crystal nickel nanowire in tensile test along [0 0 1] orientation

“…The simulations in this paper are all processed via Large-scale Atomic/Molecular Massively Parallel Simulator code developed by Sandia National Laboratory, which has been extensively used to calculate Single crystal nickel nanowire in tensile test all kinds of properties of materials [13][14][15]. We choose embedded-atom method potential to describe the interaction between atoms in this paper, which is one of the most popular interatomic potentials for materials, especially for metallic materials [16].…”

The Impact of High Pressure, Doping and the Size of Crystalline Boron Grains on Creation of High-Field Pinning Centers in In Situ MgB2 Wires

“…Previous studies show that the hot isostatic pressing (HIP) process yielded MgB 2 superconducting material with smaller grains and higher density of connections between grains [14][15][16]. The HIP process increases the homogeneity and density of dislocations [17,18]. It leads to an increase in critical current density (J c ) and irreversibility field (B irr ) [19].…”