Effect of Rolling Speed on Microstructural and Microtextural Evolution of Nb Tubes during Caliber-Rolling Process

Abstract

This study investigated the fabrication of Nb tubes via the caliber-rolling process at various rolling speeds from 1.4 m/min to 9.9 m/min at ambient temperature, and the effect of the caliber-rolling speed on the microstructural and microtextural evolution of the Nb tubes. The caliber-rolling process affected the grain refinement when the Nb tube had a higher fraction of low angle grain boundaries. However, the grain size was identical regardless of the rolling speed. The dislocation density of the Nb tubes increased with the caliber-rolling speed according to the Orowan equation. The reduction of intensity for the <111> fiber texture and the development of the <112> fiber texture with the increase of the strain rate are considered to have decreased the internal energy by increasing the fraction of the low-energy Σ3 boundaries.

Mechanical properties, microstructure, and texture evolution of copper sheets subjected to differential speed rolling process

“…In contrast with the ND plane, the fraction of misorientations with a lower angle largely decreased in the TD plane. It is proposed herein that the presence of both Σ3-type and Σ9-type twin boundaries at RSR=3 (figure 3(c)), the so-called coincidence site lattice (CSL) boundary, might demonstrate recovery because the CSL boundaries are simplified due to merging of closest-neighbor atoms by the heat generated during severe plastic deformation [20,32]. In this study, the temperature of the surface of the copper sheets increased from ∼15 °C for the as-received samples to ∼55 °C for the sample rolled at RSR=3.…”

Processing–Structure–Property Relationships in Metals

“…The book gathers manuscripts from academic and industrial researchers with stimulating new ideas and original results. It consists of one review paper regarding state of art and perspectives of alloys for aeronautic applications [1] and fifteen research papers [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] focused on different materials and processes.…”

“…Another relevant contribution to the Special Issue is provided by Lee and Jeong [12]. The authors study the effect of the calibre-rolling speed on the microstructure and microtexture of Nb tubes used as superconductivity materials.…”

Effect of strains on textural evolution of hydrostatically extruded niobium tubes

“…Below certain temperatures, materials incorporating Nb such as NbTi (10 K), Nb 3 Sn (18 K), Nb 3 Al (18 K), and MgB 2 /Nb/Cu (39 K) exhibit superconductive properties, making them viable for use in the magnet system of a magnetic resonance imaging (MRI) machine in the form of tubes [1][2][3]. For the production of tubes from MgB 2 /Nb/Cu superconductive materials, Nb tubes are initially assembled with MgB 2 powder in the form of a rod of diameter > 10 mm [4,5]. These rods are then drawn into wires with a diameter of < 1 mm for the use of MRI magnets.…”