Effect of medium-density direct current on dendrites of directionally solidified Pb–50Sn alloy. Issue 18 (11th December 2016)

• Record Type: Journal Article
• Authors: Zhang, L. M.; Li, N.; Zhang, R.; Xing, H.; Song, K.; Wang, J. Y.
• Is Part Of: Materials science and technology. Volume 32:Issue 18(2016)
• Page Start: 1877
• Page End: 1885
• Publication Date: 2016-12-11
• Subjects: Directional solidification -- Direct current -- Dendrites -- Cooling behaviours; Materials science -- Periodicals; Microstructure -- Periodicals; Metallurgy -- Periodicals; 620.1105
• DOI: 10.1080/02670836.2016.1149677
• Languages: English
• ISSNs: 0267-0836

Abstract

Abstract : This paper investigated the effect of coupling of direct current (DC) and pulling rate on dendrites and cooling behaviours of directionally solidified Pb–50Sn alloy. Experimental results indicated that the secondary dendritic arm spacing (SDAS) decreased and temperature gradient increased as increasing current densities. Moreover, temperature rise and SDAS under positive DC were higher than those under negative DC. It was speculated that Joule heating and electromigration were obviously induced by the present DC. The effect of DC on the microstructure and solidification parameters was weakened as the pulling rate increases. The coarsening rate reduced from tf 1/3 toward a value of tf 0.29 when DC of ±200 A cm –2 were applied. The refinement mechanism of SDAS was discussed.