A series Co-（18.5–20.7） at.% B melts encompassing the eutectic composition（Co81.5B18.5） were solidified at different degrees of undercooling. It is found that the metastable Co23B6 phase solidifies as a substitut...A series Co-（18.5–20.7） at.% B melts encompassing the eutectic composition（Co81.5B18.5） were solidified at different degrees of undercooling. It is found that the metastable Co23B6 phase solidifies as a substitute for the stable Co3 B phase in the alloy melts undercooled above a critical undercooling value of -60 K.The Co23B6 and α-Co phases make up a metastable eutectic. The corresponding eutectic composition and temperature are Co80.4B19.6 and 1343 K, respectively. On exposure of the metastable Co23B6 phase at a given temperature above 1208 K, it does not decompose even after several hours. But it transforms by a eutectoid reaction to α-Co ＋ Co3 B at lower temperature.展开更多
As an advanced manufacturing technique,the advent of additive manufacturing(AM) has opened a new horizon of alternative ways to tackle the challenge of fundamental limits for manufacturing bulk metallic glasses(BMGs)....As an advanced manufacturing technique,the advent of additive manufacturing(AM) has opened a new horizon of alternative ways to tackle the challenge of fundamental limits for manufacturing bulk metallic glasses(BMGs).In particular,selective laser melting(SLM),direct metal deposition(DMD),electron beam melting(EBM),and laser foil printing(LFP) have been used for producing BMGs with dimensions larger than what is possible using conventional techniques such as melt-spinning,suction-casting,die-casting,etc.In this review,we analyzed the current status,issues,structural evolution,and key properties of BMGs based on these emerging AM technologies.The aim is to outline a direction for the development of BMGs using AM technology,establishing a fundamental principle to optimize processing parameters for designing alloy compositions with the high glass-forming ability(GFA),and thermal stability against crystallization.This will provide the fundamental science underpinning the future development of AM technology in the fabrication of high-density,defect-free,and completely amorphous alloy components and devices.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.51227001 and 51471108)the SJTU-UNSW Cooperative Research Fund(16X120030005)
文摘A series Co-（18.5–20.7） at.% B melts encompassing the eutectic composition（Co81.5B18.5） were solidified at different degrees of undercooling. It is found that the metastable Co23B6 phase solidifies as a substitute for the stable Co3 B phase in the alloy melts undercooled above a critical undercooling value of -60 K.The Co23B6 and α-Co phases make up a metastable eutectic. The corresponding eutectic composition and temperature are Co80.4B19.6 and 1343 K, respectively. On exposure of the metastable Co23B6 phase at a given temperature above 1208 K, it does not decompose even after several hours. But it transforms by a eutectoid reaction to α-Co ＋ Co3 B at lower temperature.
基金financially supported by the Australian Research Council Discovery Program (No. DP190103661)。
文摘As an advanced manufacturing technique,the advent of additive manufacturing(AM) has opened a new horizon of alternative ways to tackle the challenge of fundamental limits for manufacturing bulk metallic glasses(BMGs).In particular,selective laser melting(SLM),direct metal deposition(DMD),electron beam melting(EBM),and laser foil printing(LFP) have been used for producing BMGs with dimensions larger than what is possible using conventional techniques such as melt-spinning,suction-casting,die-casting,etc.In this review,we analyzed the current status,issues,structural evolution,and key properties of BMGs based on these emerging AM technologies.The aim is to outline a direction for the development of BMGs using AM technology,establishing a fundamental principle to optimize processing parameters for designing alloy compositions with the high glass-forming ability(GFA),and thermal stability against crystallization.This will provide the fundamental science underpinning the future development of AM technology in the fabrication of high-density,defect-free,and completely amorphous alloy components and devices.
