Dependency of microindentation hardness on solidification processing parameters and cellular spacing in the directionally solidified Al based alloys

Al based alloys (Al–0.1 wt.%Ti, Al–0.5 wt.%Ti and Al–2 wt.%Li) were prepared using metals of 99.99% high purity in the vacuum atmosphere. These alloys were directionally solidified upward with the different temperature gradients, G, at a constant growth rate, V, and also with the different V at a constant G in the directional solidification apparatus. Cellular spacing, � , and microindentation hardness, HV, were measured from both transverse and longitudinal sections of the specimen as a function of solidification processing parameters (G, V and cooling rate, ˙ T ). Dependency of microindentation hardness on the solidification processing parameters and cellular spacing (� ) in the directionally solidified aluminum alloys were experimentally investigated and the relationships between the solidification processing parameters and microindentation hardness, and cellular spacing and microindentation hardness were obtained by linear regression analysis. The results obtained in this work have been compared with the previous similar experimental results obtained for binary alloys. © 2008 Elsevier B.V. All rights reserved.

[1]  A. Ülgen,et al.  Effect of the temperature gradient, growth rate, and the interflake spacing on the microhardness in the directionally solidified Al-Si eutectic alloy , 2003 .

[2]  M. Umemoto,et al.  The Hall-Petch Relationship in Nanocrystalline Materials , 1997 .

[3]  D. Ma,et al.  Laser resolidification of a Zn–3.37 wt.% Cu peritectic alloy , 2001 .

[4]  K. Okazaki,et al.  Microindentation of aluminum , 2004 .

[5]  J. Heinrich,et al.  Permeability for cross flow through columnar-dendritic alloys , 1995 .

[6]  A. Telli,et al.  Effect of antimony additions on hardness and tensile properties of directionally solidified Al–Si eutectic alloy , 1988 .

[7]  F. Vnuk,et al.  Mechanical properties of the Sn-Zn eutectic alloys , 1980 .

[8]  A. H. Yegneswaran,et al.  Effect of interlamellar spacing on the mechanical properties of 0.65% C steel , 2001 .

[9]  O. Uzun,et al.  Rapidly solidified Al–6.5 wt.% Ni alloy , 2003 .

[10]  J. Bigot,et al.  Influence of cooling rate on microstructure and mechanical properties of a Ti–48Al alloy , 1999 .

[11]  R. Elliott,et al.  Hardness and mechanical property relationships in directionally solidified aluminium-silicon eutectic alloys with different silicon morphologies , 1993, Journal of Materials Science.

[12]  J. Lapin,et al.  Directional solidification of intermetallic Ti–46Al–2W–0.5Si alloy in alumina moulds , 2002 .

[13]  A. Kennedy,et al.  The thermal stability of TiC particles in an Al7wt.%Si alloy , 2003 .

[14]  R. Elliott,et al.  The microstructure and mechanical properties of unidirectionally solidified Al−Si alloys , 1989 .

[15]  D. R. Poirier,et al.  Permeability for flow parallel to primary dendrite arms , 1992 .

[16]  Amauri Garcia,et al.  Mechanical properties as a function of microstructure and solidification thermal variables of Al–Si castings , 2006 .

[17]  B. Saatçi,et al.  Effect of solidification processing parameters on the cellular spacings in the Al-0.1 wt% Ti and Al-0.5 wt% Ti alloys , 2007 .

[18]  N. Fatahalla,et al.  Effect of microstructure on the mechanical properties and fracture of commercial hypoeutectic Al-Si alloy modified with Na, Sb and Sr , 1999 .

[19]  E. Çadırlı,et al.  Directional cellular growth of Al-2 wt% Li bulk samples , 2009 .

[20]  O. Uzun,et al.  Effect of growth rate and lamellar spacing on microhardness in the directionally solidified Pb-Cd, Sn-Zn and Bi-Cd eutectic alloys , 2004 .

[21]  F. Yılmaz.  Structure and properties of directionally solidified AlSi hypereutectic alloys , 1990 .