Ye Pan

Magnetic properties of directionally solidified MnSb/Sb eutectic composite

MnSb is the only ferromagnetic compound in the first-row transition-metal antimonides; it is highly anisotropic and proposed to be an important magnetic material for a variety of potential applications. The controlled eutectics consisting of MnSb and other components may constitute functional in-situ composites without any contamination and wetting problem between the components because of multiphase cooperative growth. The anisotropic MnSb/Sb composite is expected to possess interesting magnetic properties if MnSb is embedded in a diamagnetic antimony matrix as regular eutectic by directional solidification. However, very little has been published on MnSb/Sb eutectic composites. In the composite, the shape, size, orientation and distribution of magnetic components are important parameters which determine the quality of the materials. Consideration of these factors leads to the investigation on the relationships between microstructure, magnetic property and temperature dependence of the property in this system.

Investigation on Formation Mechanism of Irregular Shape Porosity in Hypoeutectic Aluminum Alloy by X-Ray Real Time Observation

The formation mechanism of irregular shape porosity in hypoeutectic aluminum silicon alloy (A356) was investigated by X-ray real time observation on porosity evolution during solidification and re-melting. Porosity in the hypoeutectic aluminum A356 alloy with high hydrogen content (>0.3xa0mL/100xa0gxa0Al) first forms in the liquid as small spherical gas bubbles, then expands along with the pressure drop in the mushy zone due to shrinkage and lack of feeding, and finally deforms into irregular morphology by the impingement of aluminum dendrite network. Degassing is a key to eliminate porosity in aluminum alloy castings.