ABSTRACT The in-situ TiB2/Al alloy composites are widely used in the aerospace industry due to excellent properties. Although TiB2/Al alloy composites have been investigated with regard to tool wear, surface defects and cutting force, chip formation is not widely covered but is crucial to understand the machinability. Therefore, milling experiments were conducted to research chip formation, evolution from continuous chips to serrated chips, and machined surface quality. The results show that the chip morphology presented two main forms: continuous chips and serrated chips. The shear angles of the chip tend to be 45° as feed per tooth increases. Compared with TiB2/7075 composites, the chip surfaces of TiB2/2024 composites are more rugged and prone to crack. Some cracks of chips propagate from the bottom to the inside of chips in milling of TiB2/2024 composite, but no similar phenomena appear at the chip surfaces in milling of TiB2/7075 composite. Furthermore, TiB2/Al alloy composites possess better-machined surface quality. Serrated chips deterioration machined surface quality due to the tool vibration.

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TiB2/Al合金复合材料铣削切屑形成及表面质量的实验研究

摘要 原位 TiB2/Al 合金复合材料由于其优异的性能被广泛应用于航空航天工业。尽管已经在刀具磨损、表面缺陷和切削力方面对 TiB2/Al 合金复合材料进行了研究，但切屑形成并未被广泛涵盖，但对于了解可加工性至关重要。因此，进行铣削实验以研究切屑形成、从连续切屑到锯齿状切屑的演变以及加工表面质量。结果表明，切屑形态呈现出两种主要形式：连续切屑和锯齿状切屑。随着每齿进给量的增加，切屑的剪切角趋向于 45°。与 TiB2/7075 复合材料相比，TiB2/2024 复合材料的切屑表面更粗糙，更容易产生裂纹。铣削TiB2/2024复合材料时，部分切屑裂纹从切屑底部扩展到切屑内部，但铣削TiB2/7075复合材料时切屑表面未出现类似现象。此外，TiB2/Al 合金复合材料具有更好的加工表面质量。由于刀具振动，锯齿状切屑会降低加工表面质量。