Processing of Al-45Sn-10Cu Based Immiscible Alloy by a Rheomixing Process

Abstract

The growing importance of Al-Sn based alloys for producing self lubricating bearing materials in automotive industries necessitates the development of new alloys for improved performance. The recent thermodynamic work by Schmid-Fetzer at Clausthal University of Technology predicted that the addition of Cu to the binary Al-Sn system makes the miscibility gap stable. With the guidance of the calculated phase diagram, experimental investigations were conducted on the ternary Al-Sn-Cu system to understand the solidification behaviour of this immiscible system under intensive forced convection. The experimental focus was to investigate the effects of shear rate, shearing temperature and cooling rate on the solidified microstructure.

Solidification of Al-Sn-Cu Based Immiscible Alloys under Intense Shearing

“…[4] The combination of the two alloy additions provides a soft and ductile dispersed phase in a hard and strong matrix, producing alloys appropriate for bearing applications. [1][2][3][4][5][6][7][8][9][10] One of the major challenges in the processing of Al-Sn-Cu alloys is that there is a large stable liquid miscibility gap in the system, through which many technical alloys must pass during solidification. This liquid immiscibility causes severe segregation mainly due to the large density difference between the Al-rich and Sn-rich liquids, compounded by large temperature gradient during solidification.…”

The Influence of Cooling Rate on the Microstructure and Microsegregation in Al–30Sn Binary Alloy

“…Extensive research has been conducted on different aspects of solidification processing of Al-Sn and Al-Sn-based alloys including dendrite arm spacing [1,3,8], simulation of structure formation during solidification [6,9], columnar-toequiaxed transition in directional solidification [10,11], and on the effects of other alloying elements on the solidification behavior of binary Al-Sn alloys [12][13][14][15][16]. Despite the wide Increasing cooling rate was reported to increase solid solubility and hence decrease the microsegregation and therefore the second phase content [17,18].…”