S. Madeira

Pressure and sintering temperature influence on the interface reaction of SiCp/410L stainless steel composites

This study is concerned with the reactivity between SiC particles and 410L stainless steel alloy. An interval of sintering temperatures (900, 1000, 1100, and 1180℃) was scoped in order to study the temperature influence on the interface reaction under different compaction pressures (400, 800, and 1200u2009MPa). SiCp/410L SS composites were produced by powder metallurgy. Interface area fraction (%) results and microstructural characterization showed that the interface reaction is strongly dependent on temperature. At 900℃ no reaction SiCp/410L SS was found. At 1000℃ SiCp reacts with 410L SS matrix and with increasing temperature the extent of reaction becomes higher. However, at 1180℃ SiCp dissolves completely leading to specimen deformation. The higher interface area fraction was obtained at a sintering temperature of 1100℃ and a compaction pressure of 1200u2009MPa. This study presents an advantageous and original combination of materials and process that allows combining compaction pressure and sintering temperature in order to control the interface.

A nanoindentation study on Al3Ni interface of Ni reinforced aluminum-silicon composite

ABSTRACT Aluminum-silicon (AlSi) composite reinforced with 20 wt% Ni particulates was produced by hot pressing and characterized using nanoindentation. Energy dispersive spectrometry and X-ray diffraction analyses showed that Al3Ni intermetallic was formed in the interface between Ni particulates and AlSi matrix. Chemical composition, hardness, and elastic modulus were studied along the interface from inner (near Ni) to outer (near AlSi) regions. A uniform composition was found throughout the interface, having 805.6 HV hardness and elastic modulus of 185.4 GPa. Interface properties have a crucial influence on the composite performance and their assessment is of paramount importance on composite properties estimation using predictive models.