Casting of Aluminum-Copper Based Alloy Prepared by Controlled Diffusion Solidification

摘要

This work is an attempt to improve the conventional casting technique of high strength Al-Cu-Mn-Ti series alloyrn(ZL205A) by using controlled diffusion solidification (CDS) process. A simplified element component was adopted as thernfirst step to investigate the effect of casting process on microstructure and hardness. The grain morphology and castingrndefects of this alloy prepared via the conventional casting and CDS were observed and compared at various pouringrntemperature. Results show that CDS process can alleviate the hot tearing defects and reduce the density of porosity,rnmeanwhile get rid of the riser that generally used for feeding during conventional casting. Structure observations alsornshow that the grain morphology of conventional cast alloy is mainly dendritic, the dimensions of which decreases withrndecreasing temperature, while the CDS cast alloy consists of a large number of spherical grains formed duringrnsolidification, which can improve thermal cracking tendency and segregation problems and enhance the hardness of thisrnalloy. The outstanding advantage of CDS technology with respect to Al-Cu-Mn-Ti alloy is obtaining numerous refinedrngrains and simultaneously eliminating the typical dendrites network structure when melt liquid to freeze.