The effects of crystallization on the corrosion resistance of a Cu52.5Ti30Zr11.5Ni6 bulk amorphous alloy in 1 mol/L HCl, and 6 mol/L NaOH solutions were studied. The amorphous alloy was identified by differential ther...The effects of crystallization on the corrosion resistance of a Cu52.5Ti30Zr11.5Ni6 bulk amorphous alloy in 1 mol/L HCl, and 6 mol/L NaOH solutions were studied. The amorphous alloy was identified by differential thermal analysis(DSC) and by X-ray diffraction(XRD). The partially and fully crystallized alloys were prepared by controlling the annealing temperatures at 738 and 873 K for 1 and 12 min, respectively, and the corrosion resistances of those annealed alloys were compared with that of the amorphous alloy by immersion test and potentiodynamic measurements in 1 mol/L HCl and 6 mol/L NaOH solutions. The results show that the partially crystallized alloy exhibits high corrosion resistance, whereas full crystallization results in deteriorated corrosion resistance compared with that of the as-cast amorphous alloy.展开更多
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
The curve of crystallization transition during continuous heating for the Zr41Ti14Cu12.5Ni10Be22.5 bulk amorphous alloy was measured by means of dilatation(Fully automatic transformation recording/measuring instrument...The curve of crystallization transition during continuous heating for the Zr41Ti14Cu12.5Ni10Be22.5 bulk amorphous alloy was measured by means of dilatation(Fully automatic transformation recording/measuring instrument) and X-ray diffraction(XRD) method. The deformation behavior of the alloy at various heating rates in the supercooled liquid region was studied. The results show that the glass transition temperature of the alloy increases slightly and the supercooled liquid region(SLR) increases significantly with increasing heating rate. The deformation amount under isobaric pressure of 1 N for the alloy in the SLR increases with increasing heating rate. As the heating rate of the alloy increases from 5 to 100 ℃/min, the amount of deformation of the alloy increases from 8.3% to 45%.展开更多
The amorphous and crystal structures of Zr 41 Ti 14 Ni 10 Cu 12.5 Be 22.5 alloy have been analyzed with X ray diffractometer. The structures of bulk amorphous Zr 41 Ti 14 Ni 10 Cu 12.5 B 22.5 alloy in solid, supercool...The amorphous and crystal structures of Zr 41 Ti 14 Ni 10 Cu 12.5 Be 22.5 alloy have been analyzed with X ray diffractometer. The structures of bulk amorphous Zr 41 Ti 14 Ni 10 Cu 12.5 B 22.5 alloy in solid, supercooled liquid and liquid states are almost of the same structure. The RDFs (Radius Distribution Function), the first coordination number, the first coordination radius, the correlation radius and atom number of the cluster were calculated for bulk amorphous Zr 41 Ti 14 Ni 10 Cu 12.5 B 22.5 alloy in different states. The first coordination sphere radii and the first coordination numbers are 0.312?nm, 11.2 in solid state, 0.301?nm, 10.932 in supercooled liquid region and 0.305?nm, 11.296 in liquid state. The crystal structure of Zr 41 Ti 14 Ni 10 Cu 12.5 B 22.5 alloy is consisted of several intermetallic compounds which are CuZr 2, Be 2Zr, etc. The reason of formation glass for this alloy is that there is a larger resistance for atoms to rearrange and form intermetallic compounds in a long range order.展开更多
基金Project(50371072) supported by the National Natural Science Foundation of ChinaProject(05FJ4048) supported by the Provincial Science and Technology Department Foundation of Hunan, China
文摘The effects of crystallization on the corrosion resistance of a Cu52.5Ti30Zr11.5Ni6 bulk amorphous alloy in 1 mol/L HCl, and 6 mol/L NaOH solutions were studied. The amorphous alloy was identified by differential thermal analysis(DSC) and by X-ray diffraction(XRD). The partially and fully crystallized alloys were prepared by controlling the annealing temperatures at 738 and 873 K for 1 and 12 min, respectively, and the corrosion resistances of those annealed alloys were compared with that of the amorphous alloy by immersion test and potentiodynamic measurements in 1 mol/L HCl and 6 mol/L NaOH solutions. The results show that the partially crystallized alloy exhibits high corrosion resistance, whereas full crystallization results in deteriorated corrosion resistance compared with that of the as-cast amorphous alloy.
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The curve of crystallization transition during continuous heating for the Zr41Ti14Cu12.5Ni10Be22.5 bulk amorphous alloy was measured by means of dilatation(Fully automatic transformation recording/measuring instrument) and X-ray diffraction(XRD) method. The deformation behavior of the alloy at various heating rates in the supercooled liquid region was studied. The results show that the glass transition temperature of the alloy increases slightly and the supercooled liquid region(SLR) increases significantly with increasing heating rate. The deformation amount under isobaric pressure of 1 N for the alloy in the SLR increases with increasing heating rate. As the heating rate of the alloy increases from 5 to 100 ℃/min, the amount of deformation of the alloy increases from 8.3% to 45%.
文摘The amorphous and crystal structures of Zr 41 Ti 14 Ni 10 Cu 12.5 Be 22.5 alloy have been analyzed with X ray diffractometer. The structures of bulk amorphous Zr 41 Ti 14 Ni 10 Cu 12.5 B 22.5 alloy in solid, supercooled liquid and liquid states are almost of the same structure. The RDFs (Radius Distribution Function), the first coordination number, the first coordination radius, the correlation radius and atom number of the cluster were calculated for bulk amorphous Zr 41 Ti 14 Ni 10 Cu 12.5 B 22.5 alloy in different states. The first coordination sphere radii and the first coordination numbers are 0.312?nm, 11.2 in solid state, 0.301?nm, 10.932 in supercooled liquid region and 0.305?nm, 11.296 in liquid state. The crystal structure of Zr 41 Ti 14 Ni 10 Cu 12.5 B 22.5 alloy is consisted of several intermetallic compounds which are CuZr 2, Be 2Zr, etc. The reason of formation glass for this alloy is that there is a larger resistance for atoms to rearrange and form intermetallic compounds in a long range order.
