In order to modify in-situ synthesized Mg_2Si particles in Mg_2Si/Mg-4Si composite, the modif ication effect of calcium-magnesia phosphate fertilizer on primary Mg_2Si phase in Mg_2Si/Mg-4Si composite was investigated...In order to modify in-situ synthesized Mg_2Si particles in Mg_2Si/Mg-4Si composite, the modif ication effect of calcium-magnesia phosphate fertilizer on primary Mg_2Si phase in Mg_2Si/Mg-4Si composite was investigated by means of X-ray diffraction(XRD), optical microscopy(OM), scanning electron microscopy(SEM) and energy dispersive spectroscopy(EDS) analysis. The results indicate that the morphology of the primary Mg_2Si phase apparently changes from coarse dendrites to f ine dispersive polygonal particles, and the mean size is decreased from 277 μm to 17 μm. With the addition of 4.0wt.% calcium-magnesia phosphate fertilizer as a modif ier, the ultimate tensile strength and elongation of the Mg_2Si/Mg-4Si composite are increased from 78.7 MPa and 2.1% to 105.2 MPa and 2.6%, as compared to those of the base composite, which is probably attributed to the formation of the phosphorous compound and the cluster of Ca compounds that acted as the heterogeneous nucleation substrates of the primary Mg_2Si particles, resulting in a ref ined distribution of these precipitates.展开更多
The effect of RE on granulation of eutectic carbide in ledeburite steel was studied. The mechanism of RE action was also discussed. The results show that by addition of RE compounds, the austenitic grains and eutectic...The effect of RE on granulation of eutectic carbide in ledeburite steel was studied. The mechanism of RE action was also discussed. The results show that by addition of RE compounds, the austenitic grains and eutectic carbide are fined, and the amount of divorced eutectic increases. Moreover, crystal defects, such as twins in M 7C 3, increase and the segregation of Cr and Mo decreases, which reduces the stability of carbide. Thus RE can accelerate the dynamic processes of eutectic carbide granulation. The satisfactory result of granulation of carbide was obtained in the ledeburite steel modified by RE compounds.展开更多
基金financially supported by the Fundamental Research Funds for Central Universities(Grant No.:XDJK2015B001)
文摘In order to modify in-situ synthesized Mg_2Si particles in Mg_2Si/Mg-4Si composite, the modif ication effect of calcium-magnesia phosphate fertilizer on primary Mg_2Si phase in Mg_2Si/Mg-4Si composite was investigated by means of X-ray diffraction(XRD), optical microscopy(OM), scanning electron microscopy(SEM) and energy dispersive spectroscopy(EDS) analysis. The results indicate that the morphology of the primary Mg_2Si phase apparently changes from coarse dendrites to f ine dispersive polygonal particles, and the mean size is decreased from 277 μm to 17 μm. With the addition of 4.0wt.% calcium-magnesia phosphate fertilizer as a modif ier, the ultimate tensile strength and elongation of the Mg_2Si/Mg-4Si composite are increased from 78.7 MPa and 2.1% to 105.2 MPa and 2.6%, as compared to those of the base composite, which is probably attributed to the formation of the phosphorous compound and the cluster of Ca compounds that acted as the heterogeneous nucleation substrates of the primary Mg_2Si particles, resulting in a ref ined distribution of these precipitates.
文摘The effect of RE on granulation of eutectic carbide in ledeburite steel was studied. The mechanism of RE action was also discussed. The results show that by addition of RE compounds, the austenitic grains and eutectic carbide are fined, and the amount of divorced eutectic increases. Moreover, crystal defects, such as twins in M 7C 3, increase and the segregation of Cr and Mo decreases, which reduces the stability of carbide. Thus RE can accelerate the dynamic processes of eutectic carbide granulation. The satisfactory result of granulation of carbide was obtained in the ledeburite steel modified by RE compounds.
