چكيده به لاتين
In this research, the effect of various amounts of aluminum on microstructure and matrix hardness of ductile cast irons produced by in-mold casting process is investigated. For this purpose, spherical graphite cast iron containing 0, 3.7, 5.5, 6.4 and 7.5 wt. % aluminum, respectively, were prepared in Y-block form via in-mold process. After casting, samples were prepared for microstructural studies, using conventional methods, and then were examined by optical and scanning electron microscopy (SEM). Chemical composition of samples were determined using quantometer, X-ray fluorescence spectroscopy (XRF) plus carbon and sulfur determination method. Phase identification done by X-ray diffraction test (XRD). The results indicate changing of the precipitated pearlite morphology during solidification as the aluminum content increases. XRD test results indicates Fe3Al and then Fe3AlC phase form respectively besides of ferrite and graphite by increasing in aluminum. The results also confirmed the presence of FeAl phase. Pearlite and ferrite phases hardness increases, 228 and 254 Vickers, respectively, by increasing aluminum content from 0 to 7.5 wt. %. Increasing in number of spheres from 168 to 668 per square millimeter, reducing the grain size from 21.4 to 8.8 micrometers, and changing the percentage of spherical graphite from 65 to 48 percent, with increasing aluminum content, also deposition of 2.4% cementite in the case of non-aluminum Sample, are other noteworthy results.
