The influence of undercooling(ΔT) on the glass formation of TiCu-based glass-forming alloys was systematically investigated by modulating the Cu mold temperature upon arc-suction casting.ΔT of the undercooled liquid...The influence of undercooling(ΔT) on the glass formation of TiCu-based glass-forming alloys was systematically investigated by modulating the Cu mold temperature upon arc-suction casting.ΔT of the undercooled liquids changed from 545 to 321 K depending on the mold temperature,which induced a significant change in the micro structure of alloys from a bulk metallic glass(BMG)composite containing crystals to a monolithic BMG.The unexpected enhancement in the glass-forming ability of the TiCu-based BMGs was mainly related to the evolution of the local chemical heterogeneity(LCH) of the glassy phases.The LCH in BMGs became more pronounced with increasing ΔT,and nuclei formed in Cu-rich regions.On the other hand,the LCH in the glassy phases gradually weakened under small ΔT conditions.Accordingly,the melt solidified into a monolithic BMG without nuclei in both Ti-rich and Cu-rich regions under small ΔT conditions.Moreover,a change in the phase stability of undercooled liquids could be expected with increasing ΔT by considering a non-classical model for the nucleation of glass-forming systems.The evolution of the liquid phase stability by modulating ΔT significantly influenced the crystallization behavior of the undercooled liquid.Understanding the microstructural evolution in the TiCu-based BMGs with changes in ΔT will assist in comprehending nanoscale chemical heterogeneities and the stability of the under cooled liquid,which could contribute to the optimization of the glass-forming behavior of BMGs with liquid phase separation and to the control of crystalline phase in BMG composites.展开更多
基金financially supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(Ministry of Science and ICT)(Nos.2021R1C1C1006279 and RS-2024-00409939)the Material Component Technology Development Program funded by the Ministry of Trade,Industry and Energy(MOTIE,Korea)and Samsung Display Co.,Ltd.(No.RS-2024-00431717)
文摘The influence of undercooling(ΔT) on the glass formation of TiCu-based glass-forming alloys was systematically investigated by modulating the Cu mold temperature upon arc-suction casting.ΔT of the undercooled liquids changed from 545 to 321 K depending on the mold temperature,which induced a significant change in the micro structure of alloys from a bulk metallic glass(BMG)composite containing crystals to a monolithic BMG.The unexpected enhancement in the glass-forming ability of the TiCu-based BMGs was mainly related to the evolution of the local chemical heterogeneity(LCH) of the glassy phases.The LCH in BMGs became more pronounced with increasing ΔT,and nuclei formed in Cu-rich regions.On the other hand,the LCH in the glassy phases gradually weakened under small ΔT conditions.Accordingly,the melt solidified into a monolithic BMG without nuclei in both Ti-rich and Cu-rich regions under small ΔT conditions.Moreover,a change in the phase stability of undercooled liquids could be expected with increasing ΔT by considering a non-classical model for the nucleation of glass-forming systems.The evolution of the liquid phase stability by modulating ΔT significantly influenced the crystallization behavior of the undercooled liquid.Understanding the microstructural evolution in the TiCu-based BMGs with changes in ΔT will assist in comprehending nanoscale chemical heterogeneities and the stability of the under cooled liquid,which could contribute to the optimization of the glass-forming behavior of BMGs with liquid phase separation and to the control of crystalline phase in BMG composites.
