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Showing 2 results for Saghafian Larijani
PLASTIC DEFORMATION BEHAVIOUR AT THE WORN SURFACE OF NOVEL CAST AL-ALLOY-TICP COMPOSITE
Saghafian Larijani H., Rainforth W. M.,
Volume 1, Issue 3 (Apr 2004)
Abstract
An AI-7wt%Si-5vol%TiCp was worn against a cast iron disc in a tri-pin-on-disc machine, under dry sliding conditions at the sliding speed of 0.24 m/s and applied loads of 6, 20 and 40 N/pin. Stress-strain (σ-ε) curves were constructed by measuring the microhardness and the equivalent strain gradients in near surface regions on the cross-sectional surface prepared parallel to sliding direction.It was shown that, both the magnitude of plastic strains and the depth of plastic deformed zones increased with the applied load. The material exhibited considerable work softening in addition to work hardening at the highest applied load. The softened layer placed just beneath the mechanical mixed layer (MML), was mostly covered with the fine fractured eutectic Si and TiC fragments most of which were associated with microcracks at Al/Si and Al/TiC interfaces. The results were discussed in terms of some of the current work hardening models.
The Wear Behavior of a Cast Al-20wt%Mg2Si Composite Thixoformed Via SIMA
M. Hamdi, H. Saghafian Larijani, S. G. Shabestari, N. Rahbari,
Volume 17, Issue 3 (September 2020)
Abstract
Aluminum matrix composites are candidate materials for aerospace and automotive industries owing to their specific properties such as high elastic modulus (E), improved strength and low wear rate. The effect of thixoforming process on the wear behavior of an Al-Mg2Si composite was studied in this paper. During applying thixoforming process, casting defects  such as macrosegration, shrinkage and porosity are being effectively reduced. These advantages are sufficient to attract more exploration works of thixoforming operation. Thermal analysis of the composite, as-cast microstructure, wear surface and subsurface area of the thixoformed alloy were  investigated. Wear behavior of  the specimens were examined using a pin-on-disk machine  based on ASTM-G99, at the applied loads of 25, 50 and 75 N and the constant sliding velocity of 0.25m/s. The worn surfaces and subsurfaces were examined by scanning electron microscopy (SEM). The experimental results indicated that the thixoformed specimens exhibited superior wear resistance than the as-cast alloy. Moreover, the dominant wear mechanism is an adhesive wear followed by the formation of a mechanical mixed layer (MML). However, a severer wear regime occurs in the as cast specimens compared with the thixoformed ones

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