Microstructures and mechanical properties of CrNb, CrNbTi, and CrNbTaTi concentrated refractory alloys

• Published in: Intermetallics Vol. 138; p. 107323
• Main Authors: Butler, T.M., Senkov, O.N., Velez, M.A., Daboiku, T.I.
• Format: Journal Article
• Language: English
• Published: Barking Elsevier Ltd 01.11.2021; Elsevier BV
• Subjects: Alloys; Chemical precipitation; Compressive strength; Ductility; High-entropy; Laves phase; Mechanical properties; Mechanical strength; Microstructure; Precipitates; Refractory; Refractory alloys; Refractory; Mechanical strength; High-entropy
• ISSN: 0966-9795; 1879-0216
• DOI: 10.1016/j.intermet.2021.107323

The microstructures and mechanical properties in compression (25 °C, 1000 °C and 1200 °C) of CrNb, CrNbTi and CrNbTaTi are reported. The CrNb alloy consisted of a Cr2Nb Laves phase matrix and Nb-rich BCC precipitates. After additions of Ti (CrNbTi alloy) the microstructure inverts to a Ti-rich BCC matrix, with Laves phase precipitates inside the matrix phase. Further additions of Ta to CrNbTi refined and decreased the volume fraction of the Laves phase particles in the CrNbTaTi alloy. CrNb exhibited limited ductility at 25 °C and 1000 °C, but became very ductile at 1200 °C and offered the highest compressive strength at all studied temperatures. CrNbTi and CrNbTaTi had better ductility, but suffered from a reduction in compressive strength. •CrNb, CrNbTi and CrNbTaTi are two-phase alloys consisting of a BCC (A2) and cubic Laves (C15) phases.•Addition of Ti to CrNb decreased high temperature strength, but increased ductility due to microstructure inversion.•Additions of Ta to CrNbTi refined the microstructure, reduced the fraction of C15 and further enhanced ductility.•CrNb exhibited the highest strength up to 1200°C, but was the most brittle at 25°C and 1000°C.•CrNbTaTi is the most ductile but the softest among the three studied alloys at 25 – 1200°C.