The role of ternary alloying elements in eutectoid transformation of U10Mo alloy part I. Microstructure evolution during arc melting and subsequent homogenization annealing in U9.8Mo0.2X alloy (X = Cr, Ni, Co)

JOURNAL OF NUCLEAR MATERIALS

卷:509

Article

Jana, Saumyadeep¹  Sweet, Lucas¹  Neal, Derek¹  Schemer-Kohrn, Alan¹  Lavender, Curt¹  Joshi, Vineet¹ 

[1] Pacific Northwest Natl Lab, POB 999, Richland, WA 99354 USA

关键词: UMo alloys;    Phase transformation;    Solidification;    Heat treatment;   

DOI  :  10.1016/j.jnucmat.2018.06.024

来源: Elsevier

【 摘 要 】

This work describes the microstructural evolution in an alloy of uranium with 10 wt.% molybdenum (U10Mo), with minor addition of a third alloying element, namely, Cr, Ni, or Co, at 0.2 wt.%. The microstructures of arc-melted buttons in the as-cast condition show significant Mo segregation. The segregation behavior of Cr, Ni, and Co was investigated through detailed scanning electron microscope imaging. A homogenization heat treatment at 900 degrees C for 48 h results in uniform Mo distribution and associated grain growth in all of the four alloys that were fabricated. Further, formation of multiple phases was noted in U-9.8 wt.% Mo-0.2 wt.% Ni and U-9.8 wt.% Mo-0.2 wt.% Co alloys after the homogenization annealing step. The greatest grain-boundary-initiated eutectoid transformation as measured by % volume fraction was observed when the homogenized U-9.8 wt.% Mo-0.2 wt.% Ni alloy was aged at 500 degrees C for 20 h. The least eutectoid transformation occurred in U10Mo. (C) 2018 Elsevier B.V. All rights reserved.

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