Creep Fracture of Copper Tricrystal along Grain Boundaries

Abstract

The major objective of the present study was to investigate the creep fracture process of a copper tricrystal having ©110ª-tilt 3, 3, 9 grain boundaries. Creep tests at 0.81 T M (T M : melting temperature on the absolute temperature scale) under 4 MPa tensile stress were carried out for three samples prepared from the same tricrystal. Grain-boundary sliding occurred along only the 9 boundary, and the triple junction of the boundaries completely suppressed the sliding. The three samples were in different stages of creep deformation. Creep fracture was initiated by sliding-induced voids along the 9 boundary. Grain-boundary damage by the void formation developed into complete separation along the 9 boundary, and the 9 boundary crack induced surface grooves along one of the 3 boundaries, arranged almost perpendicular to the tensile axis. The crack propagation resulted in the final fracture of the tricrystal along the 9 and 3 boundaries. The formation of cavities in the 3 fracture surface suggested that the final fracture occurred in a ductile manner after the neighboring grains were partly separated along the 3 boundary.

Best Papers Awarded in 2022 by <i>Materials Transactions</i>

“…In association with the awarded papers introduced above, popular topics that Materials Transactions published in recent years are grain boundary segregation 93) as Ito et al were concerned with, 4,30,49) creep deformation in a wide range of materials 94102) including tricrystals by Okada et al 103,104) and work hardening in various forms of deformation in an aluminum single crystal, 105) an A3104 aluminum alloy, 106) a Ti6Al4V alloy 107) and high-strength steels. 108) Furthermore, pitting corrosion resistance is also a popular issue reported by many research groups in terms of corrosion behavior of pure aluminum, 109) pure zirconium 110) and stainless steels.…”