The effects of acyclic liquid nitrogen(LN)treatment in a temperature range of-196℃to 50℃on the thermal and magnetic stability of Fe78Si9B13 and Fe73.5Si13.5B9Nb3Cu1 glassy ribbons have been studied.The intrinsic het...The effects of acyclic liquid nitrogen(LN)treatment in a temperature range of-196℃to 50℃on the thermal and magnetic stability of Fe78Si9B13 and Fe73.5Si13.5B9Nb3Cu1 glassy ribbons have been studied.The intrinsic heterogeneities of the metallic glasses can be activated through cryogenic thermal cycling,making irreversible structural changes after the treatment and inducing rejuvenation to the materials.The microstructural changes of both Fe-based metallic glass(MG)and nanocrystalline alloy induced by LN treatment were investigated.The experimental results show that the LN treatment could effectively rejuvenate the Fe-Si-B MGs and change their thermomechanical and magnetic properties.Based on the partially-crystallinity and well-known magnetic constants,the increase of the energy at the order of 10m J/g and magnetic domain wall movement and rotation at the order of 5-6μm and 0.5°-0.8°are found for FINEMET-type amorphous alloy after LN treatment.It is also found that LN treatment can contribute a little stored energy to the magnetic domain wall movement and magnetic domain rotation.展开更多
The effect of deep cryogenic cycle treatment(DCT)on Zr_(41.2)Ti_(13.8)Cu_(12.5)Ni_(10)Be_(22.5)(Vit-1)bulk metallic glass(BMG)prepared from high-purity raw materials was investigated.After DCT,no obvious rejuvenation ...The effect of deep cryogenic cycle treatment(DCT)on Zr_(41.2)Ti_(13.8)Cu_(12.5)Ni_(10)Be_(22.5)(Vit-1)bulk metallic glass(BMG)prepared from high-purity raw materials was investigated.After DCT,no obvious rejuvenation of the samples was detected.With an increasing number of cryogenic cycles,the hardness of the samples first decreased and then increased,the room-temperature compression plasticity first increased and then generally remained unchanged,and the impact toughness underwent almost no obvious change.The absence of rejuvenation was attributed to the high fragility index(47-50)and high glass forming ability(GFA)of the material.As lower purity of the raw materials is expected in practical applications,DCT of Vit-1 BMG prepared from low-purity raw materials was also performed.After DCT,the samples prepared with the lower-purity raw materials were clearly rejuvenated,and the room-temperature mechanical properties improved significantly.Both the compression plasticity and impact toughness reached peak values after 5 cryogenic cycles.The initial impurities(including Y and O)had a complex and comprehensive effect on the deformation mechanism of the BMG during DCT.Our findings indicate that the structural heterogeneity,fragility index,and GFA of the BMG alter the effect of DCT.展开更多
基金the National Natural Science Foundation of China(No.51871234)the National Key Research and Development Plan(No.2016YFB0300500)+2 种基金the Open Fund of Key Laboratory of Materials Preparation and Protection for Harsh Environment(Nanjing University of Aeronautics and Astronautics),Ministry of Industry and Information Technology(No.XCA19013-04)the Beijing Municipal Science&Technology Commission(No.Z191100007219006)the Key Research Program of Frontier Sciences,CAS(No.QYZDY-SSW-JSC017)。
文摘The effects of acyclic liquid nitrogen(LN)treatment in a temperature range of-196℃to 50℃on the thermal and magnetic stability of Fe78Si9B13 and Fe73.5Si13.5B9Nb3Cu1 glassy ribbons have been studied.The intrinsic heterogeneities of the metallic glasses can be activated through cryogenic thermal cycling,making irreversible structural changes after the treatment and inducing rejuvenation to the materials.The microstructural changes of both Fe-based metallic glass(MG)and nanocrystalline alloy induced by LN treatment were investigated.The experimental results show that the LN treatment could effectively rejuvenate the Fe-Si-B MGs and change their thermomechanical and magnetic properties.Based on the partially-crystallinity and well-known magnetic constants,the increase of the energy at the order of 10m J/g and magnetic domain wall movement and rotation at the order of 5-6μm and 0.5°-0.8°are found for FINEMET-type amorphous alloy after LN treatment.It is also found that LN treatment can contribute a little stored energy to the magnetic domain wall movement and magnetic domain rotation.
基金financially supported by the National Science Foundation for Distinguished Young Scholars of China(Grant No.51725504)the open funding via State Key Laboratory of Materials Processing and Die&Mould Technology(Grant No.P2019-011)+1 种基金the Guangdong Provincial Natural Science Foundation of China(Grant No.2020A1515011524)the Fundamental Research Funds for the Central Universities,HUST(Grant No.2018KFYRCPT001).
文摘The effect of deep cryogenic cycle treatment(DCT)on Zr_(41.2)Ti_(13.8)Cu_(12.5)Ni_(10)Be_(22.5)(Vit-1)bulk metallic glass(BMG)prepared from high-purity raw materials was investigated.After DCT,no obvious rejuvenation of the samples was detected.With an increasing number of cryogenic cycles,the hardness of the samples first decreased and then increased,the room-temperature compression plasticity first increased and then generally remained unchanged,and the impact toughness underwent almost no obvious change.The absence of rejuvenation was attributed to the high fragility index(47-50)and high glass forming ability(GFA)of the material.As lower purity of the raw materials is expected in practical applications,DCT of Vit-1 BMG prepared from low-purity raw materials was also performed.After DCT,the samples prepared with the lower-purity raw materials were clearly rejuvenated,and the room-temperature mechanical properties improved significantly.Both the compression plasticity and impact toughness reached peak values after 5 cryogenic cycles.The initial impurities(including Y and O)had a complex and comprehensive effect on the deformation mechanism of the BMG during DCT.Our findings indicate that the structural heterogeneity,fragility index,and GFA of the BMG alter the effect of DCT.
