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Using the Gleeble-1500D simulator, the high temperature plastic deformation behavior of SiCp/Al-Cu composite were investigated at 350-500℃ with the strain rate of 0.01-10s-1. The true stress-strain curves were obtained in the tests. Constitutive equation and processing map were established. The results show that the softening mechanism of dynamic recrystallization is a feature of high-temperature flow stress-strain curves of SiCp/A1-Cu composite, and the peak stress increases with the decrease of deformation temperature or the increase of strain rate.The flow stress behavior of the composite during hot compression deformation can be represented by a Zener-Hollomon parameter in the hyperbolic sine form. Its activation energy for hot deformation Q is 320.79kJ/mol. The stable regions and the instability regions in the processing map were identified and the microstructures in different regions of processing map were studied.There are particle breakage and void in the instability regions.

The SiC/6061 composites were produced by powder metallurgy method, with the SiC particle volume fraction being 20%, 25%, 30% respectively. The microstructures of the materials were observed by Optical Microscope. The tensile strength and Coefficient of thermal expansion (CTE) were examined. Turner and Kerner theoretical models were employed to analyse the CTE. The influences of the SiC particles volume fraction on the microstructures and performances were analyzed. The results show that with the increase of the SiC particles volume fraction in the composites, the clustering degree of the SiC particles increases in the matrix, and the CTE decreases which is close to the average of the Kerner and Turner theoretical model predictions, and the tensile strength increases but when the volume fraction of SiC particles exceeds the critical value of 30% the tensile strength of the composite decreases. And the strengthening mechanism of experimental materials was discussed. [ABSTRACT FROM AUTHOR]

A new spectrally selective solar absorber coating of TiC-WC/Al 2 O 3 tandem layer is designed and prepared on stainless steel (SS) substrate by magnetron sputtering. The coating consists of an absorptance layer (TiC-WC) and an antireflectance layer (Al 2 O 3 ) from substrate to top. The new SS/TiC-WC/Al 2 O 3 coating exhibits excellent selective absorbing properties with a high solar absorptance of 0.92 and a low thermal emittance of 0.11. The SS/TiC-WC/Al 2 O 3 coating presents a purple color, which is further investigated by chromaticity study. The thermal stability of the coating is evaluated and characterized by SEM, XRD, UV–vis–NIR spectrophotometer, Fourier transform infrared spectroscopy, and Raman spectroscopy. Experimental results indicate that the coating is highly stable in vacuum at 500 °C for 100 h with a good solar selectivity of 0.92/0.11. [ABSTRACT FROM AUTHOR]