A new investigated method on hot tearing behavior in aluminum alloys

Abstract

A new investigated method based on the applied forces for assessment on hot tearing behavior in aluminum alloys is introduced in the paper. In this method, molten metal is cast in the rod shaped mold cav ity. One side of the casting specimen is hooked by a steel bolt which restrains its free contraction and transfers the tensile forces during solidification. A steel threaded rod connected to a load cell which records the real time measurement of the tensile forces during every experiment. Thermal history is monitored by k type ther mocouple. The data of the temperature and tensile forces are acquired by a data acquisition system. Through the use of this method, it is possible to estimate the initiation of hot tearing, its propagation and cracking dur ing solidification. It is also obtained the critical tensile stress for hot tearing initiated and fractured. Experi ment is conducted with A356 alloys to investigate the accuracy of the apparatus and modify its operating parameter. Accordingly, the tensile forces curves, the temperature curves and the microstructure of the test specimen are obtained. This data provide useful information about hot tearing formation and solidification characteristics, from which their quantitative relations are derived. In this manner, the hot tearing behavior in aluminum alloys can be studied.

Tensile properties of the semi-solid state in solidifying aluminum alloys

“…Figure 1 shows the sche matic plane of this experimental apparatus [15]. The tensile test experimental apparatus combines a perma nent mold, a load cell, a data acquisition system, motor drive mechanism, load transmission unit and a framework.…”