Microstructure evolution of A380 aluminum alloy during rheological process under applied pressure

Abstract

S queeze casting can be supposed as a combination of casting and forging [1, 2]. In this process, high pressure is applied to the melt during solidification to obtain fine grains. The essence of mold-filling and feeding is rheological solidification of the alloy melt under pressure. Microstructure evolution is inevitable in this process, which affects the mold-filling and feeding in turn. Therefore, research on microstructure evolution during the rheological process under applied pressure is extremely meaningful. A great deal of scientific research has been done on the mechanism of microstructure evolution [3-10]. The basic methods of refining microstructure are: controlling nucleation, inhibiting dendrites growth, and prompting the initial solidification nucleation [3]. Based on these ideas, various techniques, such as mechanical stirring [4] , electromagnetic stirring [5] , strain induced melt activation [6] , casting using a cooling slope [7-9]

New mechanical stirring system to study the rheological behaviour of semisolid A380 second melting aluminium alloy

“…The rheological behaviour of the alloy has a crucial effect on the mould lling ability according to uid dynamics [12,13]. However, rheological behaviour and stopping the rheological mechanism of liquid-solid alloy melt are relatively complicated.…”

Research on pressure loss and filling ability of semi-solid rheological behavior in squeeze casting

“…Obviously, increasing the pouring temperature is also benefit on the filling ability of alloy melt, but it should not be too high, otherwise it would easily cause the defects of entrainment in the rheological squeeze casting [13][14]. Many studies have also shown that chemical composition and fine-grained structure were beneficial to the filling ability of aluminum alloys [15][16][17]. However, the method of calculating filling ability and pressure loss of semi-solid rheological behavior in squeeze casting is still unclear and cannot provide guidance for squeeze casting of thin-walled parts.…”