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
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.
