| 2008 №12 (03) | 2008 №12 (05) |
The Paton Welding Journal, 2008, #12, 14-17 pages
Mechanism of the effect of scandium on structure and mechanical properties of HAZ of the arc welded joints on aluminium alloy V96
Yu.A. Khokhlova, A.A. Chajka, V.E. Fedorchuk
E.O. Paton Electric Welding Institute of the NASU. 11 Kazymyr Malevych Str., 03150, Kyiv, Ukraine.Abstract
Heating of base metal in arc welding of high aluminium alloy V96 leads to melting of low-melting point (eutectic) phases along the grain boundaries in HAZ. These phases are the cause of hot cracking of HAZ, while after cooling they decrease the level of mechanical properties of the Joints. Scandium additions to the alloy slow down recrystallisation processes, thus promoting formation of a dispersed structure of the eutectic precipitates along the grain boundaries and, consequently, improvement of mechanical properties of the Joints
Keywords: aluminium alloys, arc welding, hot shortness, structural transformations, eutectic, scandium, strength, micromechanical tests, Berkovich indenter, microhardness, Young modulus, ductility coefficient
References
1. Ovsyannikov, B.V., Doroshenko, N.M., Zamyatin, V.M. (2005) Solidification cracks in ingots of high-strength aluminium alloys. Tekhnologiya Lyog. Splavov, 1–4, 117–121.2. Fridlyander, I.N. (2002) Aluminium alloys in aircraft of the 1970–1999 and 2000–2015 periods. Ibid., 4, 12–17.
3. Fridlyander, I.N., Chuistov, K.V., Berezina, A.L. et al. (1992) Aluminium-lithium alloys. Structure and properties. Kiev: Naukova Dumka.
4. Mondolfo, L.F. (1979) Structure and properties of aluminium alloys. Moscow: Metallurgiya.
5. (1977) Constitutional diagrams of aluminium- and magnesium-base systems: Refer. Book. Moscow: Nauka.
6. Volkov, V.A. (1987) Effect of alloying elements on the processes of decomposition of Al–Li and Al–Sc alloys: Syn. of Thesis for Cand. of PhM Sci. Degree. Kiev.
7. Berezina, A.L., Volkov, V.A., Domashnikova, B.P. et al. (1987) Some peculiarities of decomposition of oversaturated solid solution of Al–Sc system alloys. Metallofizika, 9(5), 43–45.
8. Grigorovich, V.K. (1976) Hardness and microhardness of metals. Moscow: Nauka.
9. Oliver, W.C., Pharr, G.M. (2004) Measurement of hardness and elastic modulus by instrumented indentation: advances in understanding and refinements to methodology. J. Mater. Res., 19, 3–20