MMCs reinforced with quasicrystals

Other very attractive candidates as reinforcements for MMCs are the quasicrystals (QCs). In particular, Al-Cu-Fe quasicrystals can serve as an effective reinforcement due to their high hardness (1000 HV), stiffness and, most importantly, good matrix-reinforcement interfacial bonding, which is necessary for a homogeneous distribution of the load. The good interfacial bonding results from the positive combination of physical and mechanical properties of quasicrystals, which includes low adhesion behavior, low friction coefficient, high wear resistance, low thermal conductivity and compatible thermal expansion coefficient. Good stability of the mechanical strength to temperatures above 800 K and low costs of the constituting elements can further enhance the prospects of QC-reinforced MMCs.

In our work [1], Al-based metal matrix composites containing different volume fractions of Al62.5Cu25Fe12.5 quasicrystalline reinforcing particles have been produced by powder metallurgy and the effect of volume fraction and particle size of the reinforcement on the mechanical properties of the composites has been studied in detail. Quasicrystalline particles are effective reinforcements: the yield strength increases from 110 MPa for pure Al to 135, 200 and 400 MPa for the samples reinforced with 20, 40 and 60 vol.% of quasicrystals (Figure). The model that simultaneously considers the combined strengthening contributions of load bearing, dislocation strengthening and matrix ligament size effects, which has been found to accurately describe the mechanical behavior of Al-based composites reinforced with CMAs, has been used to predict the mechanical properties of the Al-based MMCs reinforced with quasicrystalline particles. The results further demonstrate the validity of this model and confirm the importance of the characteristic matrix ligament size for explaining the strengthening effect of the composites containing large volume fractions of reinforcement.

Yield strength of the composites reinforced with Al62.5Cu25Fe12.5 quasicrystals as a function of the volume fraction of reinforcement. Experimental data (points): • present work, ∇ Schurack et al. [2] and ο Fleury et al. [3]. Calculated values (lines) from f1 (load bearing effect), fd (dislocation strengthening) and fs (matrix ligament size) [1].

[1] F. Ali, S. Scudino, G. Liu, V.C. Srivastava, N.K. Mukhopadhyay, M. Samadi Khoshkhoo, K.G. Prashanth, V. Uhlenwinkel, M. Calin, J. Eckert, J. Alloys Comp. 536S (2012) 130.
[2] F. Schurack, J. Eckert, L. Schultz, Phil. Mag. 83 (2003) 1287.
[3] E. Fleury, S.M. Lee, G. Choi, W.T. Kim, D.H. Kim, J. Mater. Sci. 36 (2001) 963.

Research group

Solidification Processes and Complex Structures

Contact person

Dr. Sergio Scudino

Phone: +49 351 4659 838
Email:  s.scudino(@t)




Devices and techniques