Microstructural Stability of a Niobium Single Crystal Deformed by Equal Channel Angular Pressing

Abstract

A [211]-oriented niobium single crystal was deformed by equal channel angular pressing (ECAP) at room temperature using the route B c to a total strain of 9.2. A sharp cube texture develops after ECAP processing. The deformed samples were annealed in vacuum from 400ºC (673 K) to 900ºC (1173 K) for 1 h to evaluate their microstructural stability. Scanning electron microscopy (SEM) was used to image the microstructures of as-deformed and annealed specimens. Electron backscatter diffraction (EBSD) was employed to determine the respective microtextures before and after annealing. Coarsening of the microstructure occurs at a maximum rate at 550ºC (823 K) due to discontinuous recrystallization. Normal grain growth replaces discontinuous recrystallization as the main coarsening mechanism above 700ºC (973 K).

Large Delta T Thermal Cycling Induced Stress Accelerates Equilibrium and Transformation in Super DSS

“…Consequently, the number of HAGB grains increased and the δ:γ ratio was the ideal 1:1, in contrast to the unchanged misoriented angles of γ grains in Figure 6b. It is noted that the misorientation angle distributions do not account for boundaries with misorientations below 2 • because of the intrinsic limitations of the EBSD technique [35].…”

“…Consequently, the number of HAGB grains increased and the δ:γ ratio was the ideal 1:1, in contrast to the unchanged misoriented angles of γ grains in Figure 6b. It is noted that the misorientation angle distributions do not account for boundaries with misorientations below 2° because of the intrinsic limitations of the EBSD technique [35]. The KAM mapping and the distribution of number fractions versus KAM below 5 • represented local plastic strain in green in mapping under the thermal cycling condition.…”

A study on interfacial activities between Nb and liquid Al in static and dynamic condition

“…However, these materials are rare and costly, and very narrow information has been recorded on their potential as a useful metal [1]. For several engineering applications and different operating environments including elevated temperature application, Nb is a suitable material [2]. Also, Nb is a body-centered cubic (BCC) material and it possesses properties like high melting point along with modest mass density, good biocompatibility, high ductility, and decent corrosion resistance [2,3].…”

“…For several engineering applications and different operating environments including elevated temperature application, Nb is a suitable material [2]. Also, Nb is a body-centered cubic (BCC) material and it possesses properties like high melting point along with modest mass density, good biocompatibility, high ductility, and decent corrosion resistance [2,3]. However, high-purity niobium has a limited application where higher mechanical strength is needed as it is very soft in nature [2].…”

“…Also, Nb is a body-centered cubic (BCC) material and it possesses properties like high melting point along with modest mass density, good biocompatibility, high ductility, and decent corrosion resistance [2,3]. However, high-purity niobium has a limited application where higher mechanical strength is needed as it is very soft in nature [2]. Due to its superior property in special conditions, Niobium has attracted the interest of many researchers recently.…”