**6. References**


• MML with high Fe content tended to be comprised of fragmented particulate, while a

• A linear relationship between specific wear rate and the thickness of the MML was observed for 2124, 5056 and 3004, but not for 6092. The specific wear rate was relatively insensitive to MML thickness for the 3004 and 5056. In contrast, for the 2124 and particularly for the 6092, the specific wear rate was a strong function of the MML

The financial support of this research through JPA/SLAB (UKM) program, under the guidance of Professor William Mark Rainforth from University of Sheffield is gratefully

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Chen L.H., and Rigney, D. A. (1986). Transfer during unlubricated sliding wear of selected

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Eyre, T.S. (1979), *Treatise on Materials Science and Tech*., edited by Scott, D., Academic Press,

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thickness.

acknowledged.

**6. References** 

**5. Acknowledgment** 

International).

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**Comparison of Energy-Based and** 

Eichlseder Wilfried, Winter Gerhard, Minichmayr Robert and Riedler Martin

*Montanuniversität Leoben* 

*Austria* 

**Damage-Related Fatigue Life Models for** 

**Aluminium Components Under TMF Loading** 

Thermo-mechanical fatigue is generally due to a cyclic thermal load in conjunction with restrained thermal expansion. Because of the considerable amplitude of strain this load leads to local cyclic plastic deformation and thus to material fatigue. Usually several concurrent and complex damage mechanisms are involved in thermo-mechanical fatigue due to the temperatures and stresses attained. In addition to typical fatigue damage caused by plastic deformation, elevated temperature leads to an increase in corrosive effects (e.g. oxidation) and creep damage. The areas of application are manifold: besides thermomechanical fatigue of combustion engine components (e.g. cylinder heads, pistons, exhaust elbows) such effects are common with tanks used in the chemical industry, pipelines, braking systems, turbine blades, as well as all machine tool components and components subjected to elevated operating temperatures. All these applications show cyclic thermal load which, for example, is caused by start-up and shutdown procedures, as well as a mechanical load caused by either restrained thermal expansion (e.g. cylinder heads) or

While in 1992 the maximum specific power for a diesel passenger car was 35 kW/l, the typical ignition pressure was about 130 bar, resulting in a maximum piston temperature of 330 °C. Owing to demands targeting reduction of costs, emissions and fuel consumption, an increase in efficiency by means of "Downsizing" is called for. This is realised by reducing the cubic capacity as well as the number of cylinders and along with additional charging, resulting in an increase in firing pressures and temperature the combustion chamber. The specific power thus obtained is in the region of 70 kW/l, together with ignition pressures of

Modern cylinder head materials are typically produced out of aluminium-cast alloys, of which aluminium-silicon-magnesium (AlSiMg) and aluminium-silicon-copper (AlSiCu) alloys are most common. Aluminium and silicon form a eutectic at 577°C and 12 weight percent. The Al-solid solution, silicon and additional secondary phases have a eutectic solidification. The cooling rate influences the dendrite arm spacing (DAS) and the morphology of the eutectic silicon. A high cooling rate leads to a low DAS and finer secondary microstructure. The hypoeutectic alloys are used for cylinder heads and

200 bar and a maximum piston temperature of more than 400 °C, (Reichstein, 2005).

**1. Introduction** 

considerable centrifugal forces (e.g. turbine blades).

hypereutectic alloys are found in pistons and crankcases.

Zhang, J., Alpas, T. A. (1997). Transition Between Mild and Severe Wear in Aluminium Alloys, *Acta Metall.,* Vol. 45, pp. 513–528. **14** 
