Effect of electron concentration on the Laves phase stability of NbCr2-Ni produced by powder metallurgy

• Published in: Philosophical magazine letters Vol. 89; no. 8; pp. 465 - 473
• Main Authors: Xu, Hua, Nie, Xiao-Wu, Du, Yong, Lu, Shiqiang, Wang, Kelu
• Format: Journal Article
• Language: English
• Published: Abingdon Taylor & Francis Group 01.08.2009; Taylor & Francis
• Subjects: Applied sciences; Constant-composition solid-solid phase transformations: polymorphic, massive, and order-disorder; Cross-disciplinary physics: materials science; rheology; electron concentration; Exact sciences and technology; Laves phase; Materials science; Materials synthesis; materials processing; Metals. Metallurgy; Phase diagrams and microstructures developed by solidification and solid-solid phase transformations; phase stability; Physics; powder metallurgy; Powder metallurgy. Composite materials; Production techniques; Technology; Grain size; Densification; Intermetallic compounds; Phase transformations; C15 compound; XRD; Powder metallurgy; Mechanical alloying; Phase transitions; Hot pressing; Powder technology; Sintering; Chromium; Nickel; Laves phases; Phase stability; Thermodynamic properties; Carrier density
• ISSN: 0950-0839; 1362-3036
• DOI: 10.1080/09500830903019012

The powder metallurgy technology of mechanical alloying followed by hot-pressing consolidation has been used to obtain NbCr 2 -Ni Laves phases. High-purity Nb, Cr, and Ni crystalline powders were milled for periods up to 35 h. These powders were vacuum sintered at 1250°C for 0.5 h under 45 MPa. The phase transformations of NbCr 2 -Ni Laves phases have been investigated by X-ray diffraction. The grain size decreases and the microstrain increases with increased Ni content. Different phase transformations were observed from NbCr 2 -Ni intermetallics. It is found that the electron concentration and phase stability correlation is obeyed in the Nb-Cr-Ni systems. However, the electron concentration corresponding to the C15/C14 phase transition is found to move to a higher value (i.e. 6.103) than the predicted one (i.e. 5.88) in the literature.