Microstructure analysis of shrinkage porosity of semi solid die casting thick wall products

1 metallographic structure analysis

The optical microscope (OM) used in this experiment is axiovert 200, and the magnification is 25, 50, 100, 200 and 500. The golden photograph collected by the digital acquisition system of the equipment is generally 2048x The resolution of 1536 pixels is 96 DPI.

In the process of preparing metallographic samples, sawing, cutting, grinding, polishing and other processes are required to cut out the blank samples to be observed from the casting. First, the abrasive paper with particle size of 100, 200, 800, 1000 and 2000 is used to polish the surface to be observed. After the grinding accuracy is reached, the sample is polished with W35 polishing paste ใ€‚ Finally, wash the surface with clean water, spray alcohol and blow dry. Figure 1 shows the metallographic photos prepared by the above process.

2.Scanning tissue analysis

In this experiment, the equipment for scanning tissue analysis is jsm-7900 scanning electron microscope provided by national standard (Beijing) inspection and Certification Co., Ltd. The samples to be tested were treated with Keller solution for 15 s. Figure 2 shows an example of a scanned photograph.