Xu, Donghua and Duan, Gang and Johnson, William L. and Garland, Carol (2004) Formation and properties of new Ni-based amorphous alloys with critical casting thickness up to 5 mm. Acta Materialia, 52 (12). pp. 3493-3497. ISSN 1359-6454 http://resolver.caltech.edu/CaltechAUTHORS:XUDam04b
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New Ni-based bulk metallic glasses were synthesized in NixCua−xTiyZrb−yAl10 (a~b~45 at.%) system, based on a ternary alloy, Ni45Ti20Zr35. The additions of Al and Cu greatly increase the glass-forming ability (GFA). The best GFA is located around Ni40Cu5Ti16.5Zr28.5Al10, from which fully amorphous samples of up to 5 mm thickness were successfully fabricated by an injection mold casting method. These alloys exhibit high glass-transition temperatures Tg ~ 760 to 780 K, and relatively wide undercooled-liquid regions ΔT (defined by the difference between Tg and the first crystallization temperature Tx1 upon heating) ~ 40–50 K. Mechanical tests on these alloys show quite high Vicker's Hardness ~ 780 to 862 kg/mm^2, Young's modulus ~ 111 to 134 GPa, shear modulus ~ 40 to 50 GPa and high fracture strength ~ 2.3 to 2.4 GPa. The effect of small Si-addition and a discrepancy between GFA and ΔT are also reported. The exceptional GFA and the all-metallic compositions give these new alloys excellent promise for both scientific and engineering applications.
|Additional Information:||Copyright © 2004 Elsevier B.V. Received 2 February 2004; Revised 29 March 2004; accepted 2 April 2004. Available online 6 May 2004. The authors thank the Defense Advanced Research Projects Agency, Defense Sciences Office, for their financial support under ARO Grant No. DAAD19-01-1-0525. Dr. Theresa H. Kidd's help with acoustic measurements is also acknowledged.|
|Subject Keywords:||Metallic glasses; Ni alloys; Bulk amorphous materials; Casting; Compression test|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Gang Duan|
|Deposited On:||17 Dec 2007|
|Last Modified:||26 Dec 2012 09:44|
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