Effect of B and Cr on elastic strength and crystal structure of Ni3Al alloys under high pressure

JOURNAL OF ALLOYS AND COMPOUNDS

卷:619

Article

Raju, S. V.¹  Oni, A. A.²  Godwal, B. K.³  Yan, J.^4,5  Drozd, V.¹  Srinivasan, S.⁶  LeBeau, J. M.²  Rajan, K.⁶  Saxena, S. K.¹ 

[1] Florida Int Univ, Dept Mech Engn, CeSMEC, Miami, FL 33172 USA

[2] N Carolina State Univ, Dept Mat Sci & Engn, Raleigh, NC 27695 USA

[3] Univ Calif Berkeley, Dept Earth & Planetary Sci, Berkeley, CA 94720 USA

[4] Lawrence Berkeley Natl Lab, Adv Light Source, Berkeley, CA 94730 USA

[5] Univ Calif Santa Cruz, Dept Earth & Planetary Sci, Santa Cruz, CA 95064 USA

[6] Iowa State Univ, Dept Mat Sci & Engn, Iowa City, IA USA

关键词: Superalloys;    High pressure;    X-ray diffraction;    Nano-indentation;    Elastic properties;   

DOI  :  10.1016/j.jallcom.2014.09.012

来源: Elsevier

【 摘 要 】

Samples of Ni3Al, Ni3Al:B and Ni-Al-Cr super alloys were prepared by directional solidification method and their effect of alloying with ternary elements on the mechanical properties was investigated. In-situ X-ray diffraction studies were carried out on undoped Ni3Al, Ni3Al:B with boron 500 ppm and Ni-Al-Cr with 7.5 at.% of chromium super alloys at high pressure using diamond anvil cell. The results indicate that micro-alloying with B forms gamma'-phase (L1(2) structure), similar to the pure Ni Al-3, while Ni-Al-Cr alloy consists of gamma' precipitates in a matrix of gamma-phase (Ni-FCC structure). The crystal structure of all three alloys was stable up to 20 GPa. Micro alloying with boron increases bulk modulus of Ni3Al by 8% whereas alloying with chromium has the opposite effect decreasing the modulus by 11% when compared to undoped alloy. Further, the elastic modulus and hardness of Ni3Al, Ni3Al:B and Ni-Al-Cr alloys were determined using the nano-indentation technique, in combination with compressibility data which enabled the estimation of shear modulus and Poisson's ratio of these alloys. (C) 2014 Elsevier B.V. All rights reserved.

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