**9. References**


< http://www.aurorametals.com/vc.htm>


portions of the melt in the down sprue to be returned to the furnace whilst keeping the

Vacuum control in countergravity casting has benefited significantly from advances in control technology and instrumentation. Li et al (2008) demonstrated a pressure control system based on fuzzy-PID control and a digital valve system and achieved pressure error of less than 0.3 KPa. Other workers such as Khader et al (2008) have carried out extensive system modelling of the countergravity casting machine with the goal of developing an

Metal casting is several millennia old, and yet it continues to evolve both in areas of applications and in the technologies of implementation. The increasing relevance of aluminium alloys in modern technology, from power applications to consumer products,

The countergravity casting technique is an ingenious method for production of aluminium parts. The numerous permutations and mutations of this technique over the last four decades is a testament to its feasibility and flexibility; and a recognition of its inherent advantages. Aluminium alloy castings stand to benefit immensely from the unique attributes of the countergravity technique because the goals of net-shape casting and

Alexander, D. (2002). High-Performance Handling Handbook. MotorBooks International,

Berenberg, B. (2003). Metal Matrix Composites Advance Optoelectronics Package Design. In:

< http://www.compositesworld.com/articles/metal-matrix-composites-advance-

Bray, R. (1989). Aluminium casting process finds new applications; developments in the

Chandley, G.D.; Redemske, J.A.; Johnson, J.N.; Shah, R.C. & Mikkola, P.H.(1997). Counter-

Chandley, G.D. (1999). Use of vacuum for counter-gravity casting of metals. *Materials* 

Druschitz, A.P & Fitzgerald, D.C. (2000). Lightweight Iron and Steel Castings for

*World Congress*, ISSN 0148-7191, Detroit Michigan, March, 2000

defence industries. *Modern Casting*, 20th May 2011, Available from;

Cosworth Process have spread its application to such fields as the aerospace and

Gravity Casting Process for Making Thinwall Steel Exhaust Manifolds *Society of Automotive Engineers (SAE), Technical Papers,* March 3rd 2011., Available from:

Automotive Applications. *Proceedings of Society of Automotive Engineers (SAE) 2000* 

Aurora Metals. (2009). Vacuum Cast Impellers. March 12th 2011, Available from:

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makes it imperative to seek better, more cost-effective production routes.

superior mechanical properties are truly achievable via this method.

ISBN 978-0760309483, Osceola, Wisconsin

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optoelectronics-package-design>

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portion delimited by the valve in the moulding flask.

automatic controller for control of machine operation.

**8. Conclusion** 

**9. References** 


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Spada, A.T. (1998). Hitchiner Manufacturing Co. – Turning the Casting World Upside Down. *Modern Casting*, Vol. 88, No. 7, pp 39-43

**2** 

*Poland* 

**Intermetallic Phases** 

Grażyna Mrówka-Nowotnik

**Examination in Cast AlSi5Cu1Mg** 

**in As-Cast and T6 Condition** 

**and AlCu4Ni2Mg2 Aluminium Alloys** 

*Rzeszów University of Technology, Department of Materials Science* 

Cast Al-Si-Cu-Mg and Al-Cu-Ni-Mg alloys have a widespread application, especially in the marine structures, automotive and aircraft industry due to their excellent properties. The main alloying elements – Si, Cu, Mg and Ni, partly dissolve in the primary α-Al matrix, and to some extent present in the form of intermetallic phases. A range of different intermetallic phases may form during solidification, depending upon the overall alloy composition and crystallization condition. Their relative volume fraction, chemical composition and morphology exert significant influence on a technological properties of the alloys (Mrówka-Nowotnik G., at al., 2005; Zajac S., at al., 2002; Warmuzek M., at al. 2003). Therefore the examination of microstructure of aluminium and its alloys is one of the principal means to evaluate the evolution of phases in the materials and final products in order to determine the effect of chemical composition, fabrication, heat treatments and deformation process on the final mechanical properties, and last but not least, to evaluate the effects of new procedures of their fabrication and analyze the cause of failures (Christian, 1995; Hatch, 1984; Karabay et al., 2004). Development of morphological structures that become apparent with the examination of aluminium alloys microstructure arise simultaneously with the freezing, homogenization, preheat, hot or cold reduction, anneling, solution and precipitation heat treatment of the aluminium alloys. Therefore, the identification of intermetallic phases in aluminium alloys is very important part of complex investigation. These phases are the consequence of equilibrium and nonequilibrium reactions occurred during casting af aluminium alloy. It worth to mention that good interpretation of

microstructure relies on heaving a complete history of the samples for analysis.

Commercial aluminium alloys contains a number of second-phase particles, some of which are present because of deliberate alloying additions and others arising from common impurity elements and their interactions. Coarse intermetallic particles are formed during solidification - in the interdendric regions, or whilst the alloy is at a relatively high temperature in the solid state, for example, during homogenization, solution treatment or recrystallization (Cabibbo at al., 2003; Gupta at al., 2001; Gustafsson at al., 1998; Griger at al., 1996; Polmear, 1995; Zhen at al., 1998). They usually contain Fe and other alloying elements

**1. Introduction** 

TurboTech Precision Products Ltd. (2011). Aluminium Compressor Wheel Castings for Turbochargers, March 3rd 2011, Available from:

< http://www.turbotech.co.uk/manufacturing-process.htm>

Waterman, P.J. (2010). Understanding Core-Gas Defects Flow-3D software helps trace, predict and avoid bubble streams in metal castings. In: *Desktop Engineering, Design Engineering and Technology Magazine*, March 6th 2011, Available from: < http://www.deskeng.com/articles/aaaype.htm>
