In order to meet the requirements for producing lightweight

thin-walled and complicated aluminum alloy parts

a new casting process was put forward. Based on the vacuum counter pressure casting

the microstructure and mechanical properties of ZL114 A alloy castings with different axial diameters were investigated under the adaptive pressure regulation. The evolution of solidification microstructure and the dendrite morphology were observed by optical microscope and scanning electron microscope. The effects of holding pressure

solidification counter-pressure and graded counter-pressure on the creep properties of ZL114 A alloy specimen were emphatically analyzed

and effects of creep temperature and creep stress on the creep properties were further discussed. The results indicate that the microstructure of ZL114 A castings under controlled-pressure tends to densify

while the dendrite is obviously refined under pressure extrusion and seepage. Meanwhile

mechanism of creep fracture is dominated by grain boundary slip. The creep resistance of castings with high pressure and strong counter-pressure is significantly improved

which is attributed to the fact that the transformation of eutectic silicon structure restrains the initiation

propagation of cracks and the reduction of grain boundary micropores.