Cu47Ti34Zr11Ni8, (Cu47Ti34Zr11Ni8)99Si and (Cu47Ti34Zr11Ni8)99Al bulk metallic glass were prepared by copper mold casting method, and the thermal stability, mechanical properties and microstrucrures of them were studi...Cu47Ti34Zr11Ni8, (Cu47Ti34Zr11Ni8)99Si and (Cu47Ti34Zr11Ni8)99Al bulk metallic glass were prepared by copper mold casting method, and the thermal stability, mechanical properties and microstrucrures of them were studied. With minor alloying of Si and Al additions, the glass transition temperature (Tg), crystallization temperature (Txl) and temperature interval of supercooled liquid region△Tx (=Txl-Tg) and reduced glass transition temperature (Trg) were proved to be changed from 672 K, 734 K, 62 K, 0.575 to 691 K, 752 K, 61 K, 0.592 and to 681 K, 729 K, 48 K, 0.590, respectively. The results indicate that the glass-forming ability (GFA) are improved with minor alloying additions. And the bulk glasses also exhibits high three point-bending flexural strength. Because of the additions of Si and Al, three point-bending flexural strength and flexural modulus of the bulk glass change from 2 350 MPa, 102 GPa to 3 260 MPa, 102 GPa and 2 970 MPa, 108GPa respectively. The obvious strengthening is due to the appearance of the medium-range ordered regions with a size of 2-5 nm under the high-resolution TEM image. The reason that the mixed amorphous and nanocrystalline phases caused by minor alloying of Si and Al additions, is that Si or Al is the third kind of elements, which are different from other constituting elements, and there are a strong bonding and atoms size effects between constituting elements, which cause the glass-forming ability (GFA) and the bulk metallic glasses strength improving.展开更多
Cu47Ti34Zr11Ni8 and (Cu47Ti34Zr11Ni8)_ 99Al bulk metallic glass with size of 1mm×10mm×50mm were prepared by copper mold casting, and the influence of minor aluminium addition upon the alloy thermal sta...Cu47Ti34Zr11Ni8 and (Cu47Ti34Zr11Ni8)_ 99Al bulk metallic glass with size of 1mm×10mm×50mm were prepared by copper mold casting, and the influence of minor aluminium addition upon the alloy thermal stability and mechanical properties was studied. The results indicate that with the aluminium addition, the crystallizing behavior of the melt changes at the same cooling rate, and the crystallizing behavior of the glass changes at the same heating rate. The glass transition temperature(T_g), crystallization temperature(T_ x1), temperature interval of supercooled liquid region ΔT_x (=T_ x1-T_g) and reduced glass transition temperature (T_ rg) are proved to be changed from 672K, 734K, 62K and 0.578 to 681K, 729K, 48K and 0.590, respectively. Because of the addition of aluminium, three point-bending flexural strength and flexural modulus of the bulk glass are increased from 2350MPa and 102GPa to 2970MPa and 108GPa, respectively.展开更多
基金Prqject(50575106) supported by the National Natural Science Foundation of China Project (AB41325) supported by the Young Scholar Foundation of Nanjing University of Science and Technology
文摘Cu47Ti34Zr11Ni8, (Cu47Ti34Zr11Ni8)99Si and (Cu47Ti34Zr11Ni8)99Al bulk metallic glass were prepared by copper mold casting method, and the thermal stability, mechanical properties and microstrucrures of them were studied. With minor alloying of Si and Al additions, the glass transition temperature (Tg), crystallization temperature (Txl) and temperature interval of supercooled liquid region△Tx (=Txl-Tg) and reduced glass transition temperature (Trg) were proved to be changed from 672 K, 734 K, 62 K, 0.575 to 691 K, 752 K, 61 K, 0.592 and to 681 K, 729 K, 48 K, 0.590, respectively. The results indicate that the glass-forming ability (GFA) are improved with minor alloying additions. And the bulk glasses also exhibits high three point-bending flexural strength. Because of the additions of Si and Al, three point-bending flexural strength and flexural modulus of the bulk glass change from 2 350 MPa, 102 GPa to 3 260 MPa, 102 GPa and 2 970 MPa, 108GPa respectively. The obvious strengthening is due to the appearance of the medium-range ordered regions with a size of 2-5 nm under the high-resolution TEM image. The reason that the mixed amorphous and nanocrystalline phases caused by minor alloying of Si and Al additions, is that Si or Al is the third kind of elements, which are different from other constituting elements, and there are a strong bonding and atoms size effects between constituting elements, which cause the glass-forming ability (GFA) and the bulk metallic glasses strength improving.
文摘Cu47Ti34Zr11Ni8 and (Cu47Ti34Zr11Ni8)_ 99Al bulk metallic glass with size of 1mm×10mm×50mm were prepared by copper mold casting, and the influence of minor aluminium addition upon the alloy thermal stability and mechanical properties was studied. The results indicate that with the aluminium addition, the crystallizing behavior of the melt changes at the same cooling rate, and the crystallizing behavior of the glass changes at the same heating rate. The glass transition temperature(T_g), crystallization temperature(T_ x1), temperature interval of supercooled liquid region ΔT_x (=T_ x1-T_g) and reduced glass transition temperature (T_ rg) are proved to be changed from 672K, 734K, 62K and 0.578 to 681K, 729K, 48K and 0.590, respectively. Because of the addition of aluminium, three point-bending flexural strength and flexural modulus of the bulk glass are increased from 2350MPa and 102GPa to 2970MPa and 108GPa, respectively.
