Abstract For titanium alloy at high cutting speed, the severe tool wear will ineluctably take place diminishing the available tool life because of the high instantaneous temperature rise. Especially the WC-Co material in carbide tool will be reacted with the oxygen element in the air and generate oxide, and the tool oxidation wear is inevitable. In milling Ti–6Al–4V alloy operations, this article presents the first comprehensive investigation on the oxidation wear effect of cryogenic cooling on carbide tool compared with the conventional cooling. Based on the Gibbs free energy of the chemical reaction, the machining characteristics of the oxidation reactions were analyzed in detail. A series of machining testes were executed adopting controllable cryogenic cooling milling system. The surface and cross-section morphology and phase composition characteristics of tool were measured by SEM and XRD measuring equipments, as well as the oxidation wear mechanism of tool in cryogenic cooling. The results show that the thermal oxidation degree of the elements of WC-Co is higher in the conventional cooling processing. After cryogenic cooling intervention, oxidation reactions in tool are reduced significantly. Even the most probable reaction is disappeared, and the oxidation degree is decreased. When the temperature drops to 180 K, it has the best cooling effect. In cryogenic, the effective binding of WC crystal particle to the adhesive phase Co is a major factor for inhabiting oxidation wear of tool. The investigations indicate that the cryogenic cooling method can effectively inhibit the oxidation effect of carbide tool in milling titanium alloy process, and it improves the resist oxidation ability of tool.

中文翻译：

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深冷对WC-Co硬质合金刀具铣削钛合金氧化磨损影响的研究

摘要 对于高速切削的钛合金，由于瞬时温升较高，刀具磨损严重，刀具寿命缩短。特别是硬质合金刀具中的WC-Co材料会与空气中的氧元素发生反应生成氧化物，刀具氧化磨损在所难免。在铣削 Ti-6Al-4V 合金操作中，本文首次全面研究了低温冷却与传统冷却相比对硬质合金刀具的氧化磨损影响。基于化学反应的吉布斯自由能，详细分析了氧化反应的加工特性。采用可控低温冷却铣削系统进行了一系列加工试验。采用SEM和XRD测量设备对刀具的表面和截面形貌及相组成特征进行了测量，并研究了刀具在低温冷却下的氧化磨损机理。结果表明，常规冷却工艺中WC-Co元素的热氧化程度较高。低温冷却干预后，工具中的氧化反应显着减少。甚至最可能的反应也消失了，氧化度降低了。当温度降到180K时，冷却效果最好。在低温下，WC晶粒与黏附相Co的有效结合是抑制刀具氧化磨损的主要因素。