EFFECT OF COEXISTENCE OF SIMILAR ELEMENTS La AND Ce ON FORMATION OF (La-Ce)-Al-Cu BULK METALLIC GLASSES

2009 ◽  
Vol 23 (06n07) ◽  
pp. 1235-1240 ◽  
Author(s):  
QING YANG ◽  
SHUJIE PANG ◽  
RAN LI ◽  
TAO ZHANG
Keyword(s):  
Metallic Glasses ◽  
Electronic Structures ◽  
Bulk Metallic Glasses ◽  
Supercooled Liquid ◽  
Copper Mold ◽  
Atomic Size ◽  
Glass Forming ◽  
Copper Mold Casting ◽  
Mold Casting ◽  
Similar Elements

Bulk metallic glasses (BMGs) in pseudo-ternary ( La - Ce )- Al - Cu system with high glass-forming ability (GFA) were synthesized based on the beneficial effect of the coexistence of similar elements La and Ce with similar atomic size and various valence electronic structures on GFA. With the coexistence of La and Ce in ( La x Ce 1- x )65 Al 10 Cu 25 system, bulk metallic glasses with diameters up to 12 mm can be produced by copper mold casting. Besides the high GFA, the ( La x Ce 1- x )65 Al 10 Cu 25 BMGs with x = 0.6 and 0.7 exhibit low glass transition temperature T g around 362 K and wide supercooled liquid regions ΔT x (ΔT x = T x - T g , where T x is the onset temperature of crystallization) of about 80 K. Compared with ternary La - Al - Cu and Ce - Al - Cu systems, significant improvement of GFA for the ( La - Ce )- Al - Cu system is caused by the coexistence of similar elements La and Ce , and the mechanism is discussed from a thermodynamic viewpoint.

Improved Synthesis of Bulk Metallic Glasses by Current-Assisted Copper Mold Casting

2010 ◽  
Vol 13 (1-2) ◽  
pp. 38-42 ◽  
Author(s):  
Mihai Stoica ◽  
Andràs Bàrdos ◽  
Stefan Roth ◽  
Lajos K. Varga ◽  
Ludwig Schultz ◽  
...  
Keyword(s):  
Metallic Glasses ◽  
Bulk Metallic Glasses ◽  
Copper Mold ◽  
Copper Mold Casting ◽  
Mold Casting

Thermal stability, corrosion resistance, and surface analysis of Cu–Hf–Ti–Ni–Nb bulk metallic glasses

2009 ◽  
Vol 24 (2) ◽  
pp. 316-323 ◽  
Author(s):  
C.L. Qin ◽  
W. Zhang ◽  
K. Asami ◽  
N. Ohtsu ◽  
A. Inoue
Keyword(s):  
Thermal Stability ◽  
Corrosion Resistance ◽  
Metallic Glasses ◽  
Surface Film ◽  
Bulk Metallic Glasses ◽  
Supercooled Liquid ◽  
Supercooled Liquid Region ◽  
Liquid Region ◽  
Copper Mold Casting ◽  
Mold Casting

Bulk metallic glasses (BMGs) with high thermal stability and good corrosion resistance were synthesized in the (Cu0.6Hf0.25Ti0.15)100−x−yNiyNbx system by copper mold casting. The addition of Ni element causes an extension of a supercooled liquid region (ΔTx = Tx – Tg) from 60 K for Cu60Hf25Ti15 to 70 K for (Cu0.6Hf0.25Ti0.15)95Ni5. The simultaneous addition of Ni and Nb to the alloy is effective in improving synergistically the corrosion resistance in 1 N HCl, 3 mass% NaCl, and 1 N H2SO4 + 0.01 N NaCl solutions. The highly protective Hf-, Ti-, and Nb-enriched surface film is formed by the rapid initial preferential dissolution of Cu and Ni, which is responsible for the high corrosion resistance of the alloys in the solutions examined.

Understanding the Glass-forming Ability of Cu50Zr50 Alloys in Terms of a Metastable Eutectic

2005 ◽  
Vol 20 (9) ◽  
pp. 2307-2313 ◽  
Author(s):  
W.H. Wang ◽  
J.J. Lewandowski ◽  
A.L. Greer
Keyword(s):  
Metallic Glasses ◽  
Glass Formation ◽  
Composition Range ◽  
Intermetallic Phase ◽  
Glass Forming Ability ◽  
Copper Mold ◽  
Wide Composition Range ◽  
Glass Forming ◽  
Copper Mold Casting ◽  
Mold Casting

Interest in finding binary alloys that can form bulk metallic glasses has stimulated recent work on the Cu–Zr system, which is known to show glass formation over a wide composition range. This work focuses on copper mold casting of Cu50Zr50 (at.%), and it is shown that fully amorphous rods up to 2-mm diameter can be obtained. The primary intermetallic phase competing with glass formation on cooling is identified, and the glass-forming ability is interpreted in terms of a metastable eutectic involving this phase. Minor additions of aluminum increase the glass-forming ability: with addition of 4 at.% Al to Cu50Zr50, rods of at least 5-mm diameter can be cast fully amorphous. The improvement of glass-forming ability is related to suppression of the primary intermetallic phase.

Formation and properties of new Cu-based bulk glassy alloys with critical diameters up to 1.5 cm

2009 ◽  
Vol 24 (9) ◽  
pp. 2935-2940 ◽  
Author(s):  
Wei Zhang ◽  
Qingsheng Zhang ◽  
Chunling Qin ◽  
Akihisa Inoue
Keyword(s):  
Supercooled Liquid ◽  
Supercooled Liquid Region ◽  
Liquid Region ◽  
Copper Mold ◽  
High Fracture ◽  
Al Content ◽  
Glass Forming ◽  
Copper Mold Casting ◽  
Glassy Alloys ◽  
Mold Casting

New Cu-based bulk glassy alloys (BGAs) with high glass-forming ability (GFA) were synthesized in a Cu-Zr-Al-Ag system. As the compositions of Cu-Zr-Al-Ag alloys with lower Ag and Al content shifted to the Cu-rich range, the supercooled liquid region, reduced glass transition temperature, and γ value increased, leading to the improvement of GFA. The best GFA is located around Cu47Zr45Al5Ag3, which is close to eutectic. Fully glassy samples with diameters up to 15 mm were fabricated by copper mold casting. These Cu-based BGAs exhibit excellent mechanical properties under compression. A large Young's modulus of 104–111 GPa, high fracture strength of 1905–1942 MPa, and distinct plastic strain of 0.002–0.011 were obtained. Additionally, the BGAs also show good corrosion resistance in 1 N H2SO4 solution.

Effect of Minor Addition of Noble Elements on Microstructure and Mechanical Properties of Ti-Based Bulk Metallic Glasses

2011 ◽  
Vol 148-149 ◽  
pp. 241-244 ◽  
Author(s):  
Feng Xiang Qin ◽  
Guo Qiang Xie ◽  
Zhen Hua Dan ◽  
Akihisa Inoue
Keyword(s):  
Mechanical Properties ◽  
Plastic Strain ◽  
Shear Band ◽  
Metallic Glasses ◽  
Bulk Metallic Glasses ◽  
High Strength ◽  
Copper Mold ◽  
Copper Mold Casting ◽  
Minor Addition ◽  
Mold Casting

Ti-based bulk metallic glasses with minor addition of Ag, Au or Pt elements were prepared by copper mold casting. The Microstructure of the as-cast samples was examined by TEM. Nanoparticles identified as cubic Pd3Ti with crystal planes of (111), (200), (220) and (311) are observed in all the alloys modified by the minor addition of Ag, Au or Pt. The results revealed that the glassy/nanoparticle composited alloys exhibited high strength about 2000 MPa and plastic strain between 1.5-10% due to the inhibition of propagation of shear band.

Cu−Zr−Ti ternary bulk metallic glasses correlated with (L → Cu8Zr3 + Cu10Zr7) univariant eutectic reaction

2008 ◽  
Vol 23 (5) ◽  
pp. 1249-1257 ◽  
Author(s):  
Chun-Li Dai ◽  
Jing-Wei Deng ◽  
Ze-Xiu Zhang ◽  
Jian Xu
Keyword(s):  
Glass Transition ◽  
Metallic Glasses ◽  
Eutectic Reaction ◽  
Glass Forming Ability ◽  
Compositional Dependence ◽  
Copper Mold ◽  
Glass Forming ◽  
Copper Mold Casting ◽  
Mold Casting ◽  
Ti Content

Starting from Cu60Zr30Ti10, the compositional dependence of bulk metallic glass (BMG) formation was revisited in the Cu−Zr−Ti ternary system. It was revealed that the optimal BMG-forming composition is located at Cu60Zr33Ti7, for which a monolithic BMG rod 4 mm in diameter can be fabricated using copper mold casting. This composition is along, although slightly off, the univariant eutectic groove for the reaction (L → Cu8Zr3 + Cu10Zr7). With respect to the corresponding Cu−Zr binary alloys, Ti has a significant effect on further stabilizing the liquid, thus increasing the glass-forming ability. For the Cu60Zr40−yTiy (3 ⩽ y ⩽ 10) series BMGs, the glass transition temperature Tg decreased with increasing Ti content, at a rate of about 2.8 K/at.%. Among these BMGs, significant compositional dependence of compressive plasticity is not observed, irrespective of the Tg change. Cu60Zr33Ti7 glass exhibits maximum fracture strength around 2160 MPa.

Influence of alloying elements Ni and Nb on thermal stability and corrosion resistance of Cu-based bulk metallic glasses

2007 ◽  
Vol 22 (6) ◽  
pp. 1710-1717 ◽  
Author(s):  
C.L. Qin ◽  
W. Zhang ◽  
K. Asami ◽  
H. Kimura ◽  
A. Inoue
Keyword(s):  
Thermal Stability ◽  
Metallic Glasses ◽  
Bulk Metallic Glasses ◽  
Supercooled Liquid ◽  
Supercooled Liquid Region ◽  
Liquid Region ◽  
Surface Films ◽  
Pitting Potential ◽  
Glass Forming ◽  
Mold Casting

Bulk metallic glasses (BMGs) with critical diameters of 2.5–3 mm were synthesized in the (Cu0.6Zr0.3Ti0.1)100−x−yNiyNbxsystem by copper-mold casting. These alloys exhibit a large supercooled liquid region (ΔTx) of 40–60 K and a high reduced glass transition temperature (Tg/Tl) of 0.60–0.61, indicating high glass-forming ability and high thermal stability of the supercooled liquid. The corrosion rates in 1 N HCl and 3 mass% NaCl solutions significantly decrease by simultaneous alloying with Ni and Nb elements. The addition is also effective in raising the pitting potential in chloride solutions. The addition of Ni and Nb is favorable for the alloys in forming Zr-, Ti-, and Nb-enriched highly protective surface films in HCl and NaCl solutions.

Studies on Fe-Cr-Ni-Si-B Bulk Metallic Glass for Automotive Applications

2015 ◽  
Vol 1114 ◽  
pp. 68-75
Author(s):  
Mariana Lucaci ◽  
Delia Patroi ◽  
Violeta Tsakiris ◽  
Magdalena Valentina Lungu ◽  
Eugen Manta ◽  
...  
Keyword(s):  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Metallic Glasses ◽  
Melt Spinning ◽  
Copper Mold ◽  
Technological Parameters ◽  
Glass Forming ◽  
Copper Mold Casting ◽  
Mold Casting ◽  
Melt Spin

Researches and developments were carried out for obtaining of bulk metallic glass (BMG) from the Fe-Cr-Ni-Si-B system. The used processing methods were copper mold casting and melt spinning method. The resulted materials are in form of sheets with sizes of 69.7 x 64 x 3/1.5 mm and of strips with thickness less than 50 microns, which were obtained by varying the melt spin technological parameters. The both processing variants are not suitable for obtaining such of alloy in bulk metallic glass form. Adding of zirconium to this alloy produces bulk metallic glasses only for the melt spin products. The DSC analysis emphases that the zirconium modified alloy processed by melt spinning method exhibits a high glass forming ability (GFA).

Formation and mechanical properties of Cu–Hf–Al bulk glassy alloys with a large supercooled liquid region of over 90 K

2003 ◽  
Vol 18 (6) ◽  
pp. 1435-1440 ◽  
Author(s):  
Akihisa Inoue ◽  
Wei Zhang
Keyword(s):  
Glassy Alloy ◽  
Ternary Systems ◽  
Supercooled Liquid ◽  
Supercooled Liquid Region ◽  
Liquid Region ◽  
Copper Mold ◽  
Glass Forming ◽  
Copper Mold Casting ◽  
Glassy Alloys ◽  
Mold Casting

New Cu-based bulk glassy alloys with large supercooled liquid regions and high mechanical strength were formed in Cu–Hf–Al ternary systems. The large supercooled liquid region exceeding 70 K was obtained in the composition range of 40 at.% Hf at 2.5% Al, 37.5–50% Hf at 5% Al, and 45% Hf at 7.5% Al. The largest supercooled liquid region ΔTx(= Tx – Tg) was 91 K for Cu50Hf45Al5 alloy, and the highest reduced glass-transition temperature was 0.63 for Cu50Hf42.5Al7.5 and Cu52.5Hf40Al7.5 alloys. The alloys with large ΔTx values above 50 K were formed into bulk glassy rods with diameters up to 3 mm by copper mold casting, and the glassy alloy rods exhibited high compressive fracture strength of 2260 to 2370 MPa and Young's modulus of 121 to 128 GPa combined with elastic elongation of 1.9% to 2.0% and plastic elongation of 0.2% to 0.6%. No bulk glassy alloys were formed in the Cu–Hf binary system by copper mold casting, and, hence, the addition of 2.5% to 7.5% Al to Cu–Hf alloys was very effective for increasing glass-forming ability as well as the stabilization of supercooled liquid. The effectiveness can be interpreted on the basis of the concept of the formation of a unique glassy structure in special multicomponent alloys with the three component rules.

Formation and compression mechanical properties of Ni–Zr–Nb–Pd bulk metallic glasses

2008 ◽  
Vol 23 (7) ◽  
pp. 1940-1945 ◽  
Author(s):  
J.B. Qiang ◽  
W. Zhang ◽  
A. Inoue
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Metallic Glasses ◽  
Hydrogen Permeation ◽  
Bulk Metallic Glasses ◽  
Supercooled Liquid ◽  
Partial Substitution ◽  
High Fracture ◽  
Glass Forming ◽  
Mold Casting

The formation of bulk metallic glasses (BMGs) and their room temperature mechanical properties have been investigated in a serial of Ni65−xZr20Nb15Pdx (x = 0∼15; at.%) quaternary alloys, which are hopefully hydrogen-permeation materials. The partial substitution of Ni with Pd in Ni65Zr20Nb15 alloy has proved to be effective in improving glass-forming ability (GFA) and thermal stability. In particular, good BMG-forming compositions were revealed within the Pd content range of 2.5–12.5 at.%, and BMG rods of 3 mm in diameter were successfully made at compositions Ni57.5Zr20Nb15Pd7.5 and Ni55Zr20Nb15Pd10 by copper mold casting. The addition of Pd enhanced the thermal stability of the supercooled liquid. With an increase of Pd content, the supercooled liquid span, ΔTx = Tx − Tg, increased from 29 K at Ni65Zr20Nb15 to 47 K at Ni52.5Zr20Nb15Pd12.5. The Pd-bearing BMGs exhibited high fracture strength, which ranged from 2750 to 2850 MPa. These Pd-bearing BMGs showed a certain degree of toughness, and the highest plastic strain, about 2%, was reached in the Ni60Zr20Nb15Pd5 BMG.

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