Laser engraving / chemical milling is a hybrid manufacturing technology which is suitable for the fabrication of the key components in aerospace industries. Here, we originally proposed a molecular dynamics model to study the chemical reactions and corrosion mechanism between TA15 titanium alloy and the mixed HF-HNO 3 solution. Then, experiments on corrosions are carried out to optimise the mixing ratio of the mixed HF-HNO 3 solution. Results indicate that the corrosion mechanism in chemical milling is governed by HF-induced activation-driven dissolution and HNO 3 -mediated oxidation-induced passivation. The increase of HF ratio in the mixed solution can lead to higher surface roughness and hydrogen absorption. The increase of HNO 3 ratio in the mixed solution can lead to lower corrosion rates. A formulation is obtained to reveal the relationship between corrosion rate and concentration of HF and HNO 3 . By consideration of the corrosion rate, surface roughness and hydrogen embrittlement risk, the optimal mixed ratio is 8% HF concentration and 14% HNO 3 concentration with corrosion rate of 3.405 g·m − 2 ·s − 1 . The proposed model and the summarised formulation can provide theoretical basis and practical process parameters for chemical milling and surface treatment of TA15 titanium alloy.
Yu et al. (Sat,) studied this question.