Dissertation > Industrial Technology > General industrial technology > Materials science and engineering > Composite materials > Non-metallic composite materials

Study on Characteristics of Contiuous Fiber-Reinforced Metal Matrix Composites under Hypervelocity Projectile Impact

Author DingWei
Tutor WuGaoHui
School Harbin Institute of Technology
Course Materials Science
Keywords Hypervelocity impact Composites Damnification of impact Impact dynamics
Type Master's thesis
Year 2008
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Tif/Al composite, Tif/Cf/Al composite and Cf/Al composite were fabricated by pressure infiltration technique. Rolled LF6 aluminum alloy and the composites mentioned above were impacted by aluminum projectiles of different diameters at the speed of 2.5km/s.It can be judged from the critical diameter of the projectile staving in the material that Tif/Al composite is the best, and then the results of LF6 aluminum alloy, Tif/Cf/Al composite materials, Cf/Al composite dropped.Spark erosion wire cutting was used to dissect the sample, then followed polishing and corrosion to the section plane. Optical microscope and scanning electron microscope were used to observe the front and back and the section plane of the crater, also characters of the craters were measured. Comparing the characters of four kingds of materials above, aluminum alloy and Tif/Al composite performed plastic, and the performance of Tif/Cf/Al composites were between plastic and brittle, while Cf/Al composites performed brittle.The depth of craters in the composites caused by hypervelocity projectile impact was discussed from the aspect of impact dynamics semiquantitatively, and the resoults of analysis were consistent with the results of the experiment. The critical factors affected the depth of craters in the composites from, especially the effects of the high impendence mismatch under hypervelocity projectile impact, were given from theory.The reason for no adiabatic shear bands observed in the matrix of the composites was explained by using thermo-viscoplastic model and the results of the analysis of the depth of craters. The possible existing regions of adiabatic shear band in the composites were given from the aspect of mechanics, which was compared with the experimental results.After the analysis and explanation of the spalling phenomenon in the composites, it was found that the reason for spalling phenomenon in the composites was different from that for the aluminum alloy.After the measurement and comparison to the relationship between diametres of projectiles and the depth and width of craters, it is found that the depth of craters of Cf/Al composite is the smallest, LF6 alloy is the biggest.

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