The effect of alloying with hafnium on the thermal stability of chromium bronze after severe plastic deformation

Influence of alloying with hafnium on the microstructure, texture, and properties of Cu–Cr alloy after equal channel angular pressing

“…Decomposition of a supersaturated solid solution occurs during annealing at higher temperatures, resulting in the formation of Cr particles in the Cu-0.7 % Cr alloy [2]. The peak aging temperature (450°C) for the Cu-0.7 % Cr alloy agrees well with that previously reported for the Cu-0.5 % Cr alloy after ECAP [23]. In the alloy additionally alloyed with Hf, aging after quenching and ECAP leads to Cu 5 Hf precipitation in addition to Cr particles [3,24].…”

“…Therefore, it is expected that the strengthening effect after deformation followed by aging be more pronounced due to a higher fraction of second phases. The advantage of copper alloying with hafnium was shown for SPD by HPT [23,24]. To get a better insight into the effect of SPD on the microstructure, texture, and properties of a Cu-Cr-Hf alloy, in the present work, this alloy was investigated after ECAP with subsequent annealing and compared with Cu-Cr alloys.…”

Aging Processes in Ultrafine‐Grained Low‐Alloyed Bronzes Subjected to Equal Channel Angular Pressing

“…[1] Previous studies showed possibility of the formation of submicrocrystalline structure and efficient aging in Cr, Zr, and CrZr bronzes by SPD methods such as equal channel angular pressing (ECAP) [2][3][4][5][6][7][8][9][10][11][12][13][14][15] and highpressure torsion (HPT). [16][17][18][19][20][21][22][23] Alloying of Cu with zirconium results in increased thermal stability due to precipitation hardening and suppression of grain growth during aging. Along with strength and thermal stability increase in ultrafine-grained (UFG) low alloyed bronzes, SPD allows to improve some functional properties such as wear resistance, [13,15] electrical conductivity, [2,4,[12][13][14][19][20][21][22][23] fatigue life, [2][3][4]6] etc.…”

“…[16][17][18][19][20][21][22][23] Alloying of Cu with zirconium results in increased thermal stability due to precipitation hardening and suppression of grain growth during aging. Along with strength and thermal stability increase in ultrafine-grained (UFG) low alloyed bronzes, SPD allows to improve some functional properties such as wear resistance, [13,15] electrical conductivity, [2,4,[12][13][14][19][20][21][22][23] fatigue life, [2][3][4]6] etc. However, in terms of electrotechnical applications, the most important is the combination of high strength and electrical conductivity provided by high thermal stability.…”

“…Actually, it was shown that strength after HPT, hardening during following aging, and thermal stability of hardening in the Cu-Hf alloy are higher than in the Cu-Zr alloy. [19][20][21] In order to enhance both high strength and conductivity in UFG bronzes, it is important to find the optimal timetemperature aging regime. Earlier studies of the Cu-Cr-Zr alloys showed the effectiveness of aging, either before [4,9,14] or after ECAP.…”