The results show that the pressure, fluidity and cooling rate of liquid metal at different positions are different during solidification. Therefore, it is necessary to discuss the effect of position effect on solidification structure. Select the middle (m), bottom (b) and top (T) of the specimen (plate hammer) for sampling. With the help of commercial finite element simulation software ProCAST, the solidification sequence and temperature curve of the test block under 160 MPa pressure are simulated, and the results are shown in Fig. 1 and 2.
Figure 1 (a) (b) (c) (d) shows the results when the solid ratio is 25%, 50%, 75% and 99.9% respectively. It can be seen from the figure that when the solidification is almost completed, an isolated liquid phase zone appears in the center of the casting, and the specimen in the center of the specimen is the final solidification place of the specimen. The specimen at the top and bottom of the specimen has a great degree of supercooling in direct contact with the indenter and die during solidification, which is also the first part of the specimen to solidify.
Fig. 2 shows the cooling curves at different positions of the specimen, and the solidification rate from fast to slow is: bottom > top > middle. Combined with the solidification rate, the solidification structure of alloy 2 # at different positions under various pressures was compared, and the parameters including eutectic spacing, eutectic content, eutectic phase size, primary phase size and so on were counted to evaluate the effect of pressure at different positions.