Casting Defects in Transition Layer of Cu/Al Composite Castings Prepared Using Pouring Aluminum Method and Their Formation Mechanism

Abstract

In this study, Cu/Al composite castings were prepared using the pouring aluminum method, and the casting defects in the transition layer and their formation mechanism were investigated. Shrinkage cavities, shrinkage porosities, and cracks were easily formed in the transition layer, and the thickness of the transition layer was uneven after recombination of the solid Cu and liquid Al. Shrinkage cavities easily formed within the α + eutectic (α + CuAl2) phase, and cracks mainly appeared within the Cu9Al4 and CuAl2 phases. The transition layer with uneven thickness and irregular shape readily formed where the metals solidified last during the solidification; the difference in density between solid Cu and liquid Al, as well as the natural convection in the melt, were responsible for these irregular shapes. As the metals shrunk, shrinkage cavities and porosities formed without external melt feeding. Cracks formed in the Cu9Al4 and CuAl2 phases and at the Cu9Al4/CuAl2 and CuAl2/eutectic (α(Al + CuAl2) interfaces during the solid shrinkage process after the solidification was complete.

tomographic TESTING of alnico alloys

“…Structural integrity of materials is to be monitored to safe operation [1][2][3]. Regular periodic non-destructive investigation right from the date of installation will not only enable the user to achieve optimum safe utilization but also to alarm when untoward deterioration is caused due to different parameters [4][5][6][7]. The estimation of mechanical properties of materials can be carried out by several methods; destructive and non-destructive [8].…”

Archives of Foundry Engineering

“…These include processes that result may not be fully verified by inspection or testing of the product, and where the shortcomings of the process of manufacture may appear only during its operation. Various non-destructive testing methods can be used to detect and determine foundry incompatibilities [2][3][4][5][6]. The basic method, obligatory and commonly used is visual testing.…”