Papers by Author: Tao Wei

Abstract: There have been growing demands of high performance metal matrix composites in advanced engineering applications in virtue of their high specific strengths. This paper is to report an assessment of the mechanical properties of LC4/SiCp metal matrix composites using an innovative testing technique, small punch test. The composite materials of this study were produced by stir casting method with particulate reinforcements of 7wt.% and 14wt.% of SiC respectively. Small punch testing was performed on the LC4 base alloy and the two composites materials. The small punch test is a relatively new mechanical testing technique capable of utilizing small disk-shaped samples to determine the mechanical properties of the test materials. In this study, the equivalent fracture strain, εqf of the LC4/SiCp MMCs was characterised and compared with the base alloy. The fracture mechanism of the test samples was examined using scanning electron microscopy.

Abstract: Particulate reinforced 10 vol.% (TiB+TiC)/Ti-6Al-4V metal matrix composites (MMCs) were produced by in-situ synthesis using vacuum arc re-melting process, and the mechanical properties of the metal matrix composites were assessed by the small punch testing (SPT). Mechanical properties of the in-situ synthesized Ti MMCs were studied and compared with the Ti base alloy. From the test data, the fracture properties and equivalent fracture strain of the test materials were characterised. The fracture mechanism of the test samples was examined using scanning electron microscopy.

Abstract: The small punch test (SPT) is a relatively new mechanical testing technique capable of utilising small disk-shaped specimens to determine the mechanical behaviour of the test materials. From the test data, fracture properties in particular the equivalent fracture strain (εqf) can be determined and the elastic-plastic fracture toughness of a material can be characterised. Finite element analyses (FEA) of the small punch tests have been performed for the 304H stainless steel in this study. 304H stainless steel was isothermally aged at 650, 700 and 750oC for durations up to 200 hours. Small punch tests were performed to assess the mechanical properties of the heat treated materials. Using the input of the true stress-strain curves of material constitutive behaviour, the theoretical load vs punch displacement curves calculated from the FEA models were found in good agreement with the experimental results. The fracture thickness of the small punch tested specimens and the equivalent fracture strain were also be determined for the test materials.