先进复合材料及其制备讲义.ppt

* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * The simplified FSP machine used in this experiment was a modified form of a horizontal-type milling machine, with a 5 HP spindle. The fixed pin tool was 6 mm in diameter and 6 mm in length. The shoulder diameter was 18 mm, and a 2 tilt angle of the fixed pin tool was applied. The pitch distance was 1 mm. The advancing speed of the rotating pin was kept constant in this study to be 45 mm/min, with a fixed pin rotation of 800 rpm. The plates were fixed by a fixture and ambient air cooling was applied. In order to maintain the entire fixture at the initial temperature (room temperature) after each pass, the back plate of the fixture was designed to contain three cooling channels with cooling water passing through them. Using the methods described in a previous paper [6], the strain rate and the maximum temperature experienced during FSP are around 101 s1 and 400C, respectively. To insert the nano-SiO2 particles, one or two grooves each 6 mm in depth and 1.25 mm in width were cut, in which the nano-SiO2 particles were filled to the desired amount before FSP. The groove(s) were aligned with the central line of the rotating pin (Fig. 2b). In order to prevent the SiO2 from being displaced out of the groove(s), surface ‘‘repair’’ was accomplished with a modified FSP tool that only had a shoulder and no pin. The volume fractions of the SiO2 * Summary of Ultrasonic Processing High-intensity ultrasonicwaves are capable of distributing and dispersing nanoparticles in Mg matrix with non-linear effects in liquids, especially transient cavitation. From the high-resolution SEM observation, SiC nanoparticles are almost uniformly distributed in the matrix, although some small clusters (less than 300 nm) still exist in matrix. EDS analysis indicates that the SiC nanoparticels are partly oxidized. Compared to pure cast AZ91D, cast AZ91D/5SiC yields Mg2Si compounds. The Mg2Si compound in the com