Comparative TEM study on as-cast ingot and nodular bainite of Cu-14.9%Sn alloy

• Published in: Philosophical magazine (Abingdon, England) Vol. 94; no. 4; pp. 420 - 438
• Main Authors: Wang, Zeng-Jie, Konno, Toyohiko J.
• Format: Journal Article
• Language: English
• Published: Abingdon Taylor & Francis 01.02.2014
• Subjects: ALLOY DEVELOPMENT; Constant-composition solid-solid phase transformations: polymorphic, massive, and order-disorder; copper-tin alloy; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Materials science; orientation relationship; Phase diagrams and microstructures developed by solidification and solid-solid phase transformations; phase transformation; Physics; precipitation behaviour; Solidification; transmission electron microscopy; Delta phase; Beta phase; Transmission electron microscopy; Alpha phase; Atomic position; Plane strain; Microstructure; Eutectoids; Comparative study; Interplanar spacing; Ingot; Orientation relation
• ISSN: 1478-6435; 1478-6443
• DOI: 10.1080/14786435.2013.853886

We have investigated microstructure and orientation relationship (OR) of the α and δ phases in an as-cast ingot and nodular bainite of Cu-14.9 at.% Sn alloy by using transmission electron microscopy. Proeutectoid α grains and surrounding δ phase (prior β phase) possess well-defined (1 1 1) α //(1 1 0) δ , OR, that is, Kurdjumov-Sach (K-S) OR, while these two phases formed by eutectoid decomposition exhibit some deviation from K-S OR. On the other hand, the α and δ phases in nodular bainite exhibit (1 1 1) α //(1 1 0) δ , , which is Nishiyama-Wassermann (N-W) OR, as well as K-S OR. The emergence and variations of these ORs between the α and δ phases have been interpreted from the viewpoints of (i) matching of interplanar spacing of {1 1 1} α , {1 1 0} β and {6 6 0} δ planes, (ii) minimum strain criteria based on the invariant line concept for K-S OR and (iii) correspondence of atomic positions in the relevant phases by employing the structural ledge concept for N-W OR.