The glass forming ability, thermal and mechanical properties of some Zr Cu Al Ni bulk metallic glasses were analyzed. The compositions of the alloys were theoretically determined with the dense packing and kinetic fra...The glass forming ability, thermal and mechanical properties of some Zr Cu Al Ni bulk metallic glasses were analyzed. The compositions of the alloys were theoretically determined with the dense packing and kinetic fragility index models. Cylindrical and conical ingots were produced by copper mould suction-casting under Ar atmosphere. The conical ingots were characterized by means of X-ray diffraction in order to determine the glassy structure. It was found that both alloys have a critical glassy diameter, Dc, of 3 mm. Thermal behaviours were investigated by differential scanning calorimetry at heating rates of 0.5, 0.67 and 0.83 K/s. The gamma parameter γ, supercooled liquid region ΔTx, and reduced glass transition temperature Trg, of the experimentally obtained glasses indicated high glass forming ability. The glassy compositions showed a fragility index of ~40 GPa. The compression test of the investigated alloys was carried out at a strain rate of 0.016 s^-1, obtaining a elastic modulus of ~83 GPa, total deformation of ~5%, yield strength of 1.6 GPa and hardness of 4 GPa. It was concluded that the use of the dense packing and kinetic fragility index models helped to predict glass-forming compositions in the family alloy investigated.展开更多
In this paper the critical cooling rate, Rc, for the glass formation of Fe80P13C7 alloy has been determined using both Uhlmann＇s and Barandiaran-Colmenero＇s method. In Uhlmann＇s method, all kinds of the expres-sion...In this paper the critical cooling rate, Rc, for the glass formation of Fe80P13C7 alloy has been determined using both Uhlmann＇s and Barandiaran-Colmenero＇s method. In Uhlmann＇s method, all kinds of the expres-sions of △G^l-s （T） and η/（T） determined using the different modes and methods had been investigated. It is indicated that the Rc for the glass formation of FesoP13C7 alloy can be estimated to be 349 K/s by Uhlmann＇s method based on the appropriate expressions of △G^l-s（T） and η/（T）. The calculated result accords with our experimental result. The Rc for the glass formation of Fe80P13C7 alloy has also been determined to be 0.49 K/s using Barandiaran-Colmenero＇s method. This resultant Rc is unreasonable low and it indicates that Barandiaran-Colmenero＇s method does not suit to Fe-based alloy.展开更多
基金the financial support from UNAM-DGAPA-PAPIIT thorough the project 101016CONACYT for the 232312 Ph D scholarship grant
文摘The glass forming ability, thermal and mechanical properties of some Zr Cu Al Ni bulk metallic glasses were analyzed. The compositions of the alloys were theoretically determined with the dense packing and kinetic fragility index models. Cylindrical and conical ingots were produced by copper mould suction-casting under Ar atmosphere. The conical ingots were characterized by means of X-ray diffraction in order to determine the glassy structure. It was found that both alloys have a critical glassy diameter, Dc, of 3 mm. Thermal behaviours were investigated by differential scanning calorimetry at heating rates of 0.5, 0.67 and 0.83 K/s. The gamma parameter γ, supercooled liquid region ΔTx, and reduced glass transition temperature Trg, of the experimentally obtained glasses indicated high glass forming ability. The glassy compositions showed a fragility index of ~40 GPa. The compression test of the investigated alloys was carried out at a strain rate of 0.016 s^-1, obtaining a elastic modulus of ~83 GPa, total deformation of ~5%, yield strength of 1.6 GPa and hardness of 4 GPa. It was concluded that the use of the dense packing and kinetic fragility index models helped to predict glass-forming compositions in the family alloy investigated.
基金supported by the National Natural Science Foundation of China (No. 50861007)the Project of Supporting Xinjiang Uyghur Autonomous Region by Science and Technology (No. 201191203)the Opening Subject from State Key Laboratory of Powder Metallurgy in Central South University
文摘In this paper the critical cooling rate, Rc, for the glass formation of Fe80P13C7 alloy has been determined using both Uhlmann＇s and Barandiaran-Colmenero＇s method. In Uhlmann＇s method, all kinds of the expres-sions of △G^l-s （T） and η/（T） determined using the different modes and methods had been investigated. It is indicated that the Rc for the glass formation of FesoP13C7 alloy can be estimated to be 349 K/s by Uhlmann＇s method based on the appropriate expressions of △G^l-s（T） and η/（T）. The calculated result accords with our experimental result. The Rc for the glass formation of Fe80P13C7 alloy has also been determined to be 0.49 K/s using Barandiaran-Colmenero＇s method. This resultant Rc is unreasonable low and it indicates that Barandiaran-Colmenero＇s method does not suit to Fe-based alloy.
