(1. 南昌航空大學(xué) 輕合金加工科學(xué)與技術(shù)國防重點(diǎn)學(xué)科實(shí)驗(yàn)室，南昌 330063；
2. 南昌航空大學(xué) 材料科學(xué)與工程學(xué)院，南昌 330063；
3. 中航工業(yè)北京青云航空儀表有限公司 表面處理分廠，北京 102402)
摘 要: 采用三維視頻顯微鏡、粗糙度輪廓儀和電化學(xué)測試研究溴化鋰溶液中不同溫度條件下Ti-6Al-4V微觀空蝕形貌、粗糙度以及電化學(xué)腐蝕行為，探討溫度對空蝕的影響機(jī)理。結(jié)果表明：溫度的影響隨空蝕時(shí)間增加不斷加強(qiáng)，240 min時(shí)最為顯著，之后影響減弱并趨于穩(wěn)定。溫度升高，空泡潰滅產(chǎn)生的微射流沖擊強(qiáng)度增大，使表面鈍化膜更易被破壞，同時(shí)腐蝕作用加速了點(diǎn)蝕形成，導(dǎo)致表面局部應(yīng)力集中和更多電化學(xué)電池的產(chǎn)生，從而促進(jìn)了力學(xué)和腐蝕因素，兩者的協(xié)同作用加速了空蝕破壞。空蝕破壞程度在溫度55 ℃時(shí)達(dá)到最大值，繼續(xù)升高溫度，腐蝕因素仍被促進(jìn)，但微射流對表面的沖擊強(qiáng)度減弱，對表面鈍化膜的破壞作用降低，由于力學(xué)因素在空蝕中占據(jù)主導(dǎo)地位，因此使空蝕速率得到減緩。
關(guān)鍵字: Ti-6Al-4V合金；溴化鋰溶液；溫度；空蝕；影響機(jī)理
（1. National Defence Key Discipline Laboratory of Light Alloy Processing Science and Technology Institute, Nanchang Hangkong University, Nanchang 330063, China;
2. School of Material Science and Engineering, Nanchang Hangkong University, Nanchang 330063, China;
3. Department of Surface Treatment, Avic Beijing Keeven Aviation Instrument Co., Ltd., Beijing 102402, China）
Abstract:Three-dimensional video microscope, roughness profiler and electrochemical measurement were used to investigate the cavitation corrosion morphologies, surface roughness and electrochemical corrosion behavior of Ti-4Al-4V in LiBr solution at different temperatures. Furthermore, the influence mechanism of temperature on cavitation corrosion was discussed. The results show that the temperature effect is gradually strengthened as cavitation time increasing. It is most significant for 240 min, after that, it is reduced and tends to be stable. The rise in temperature enhances micro-jet impact strength, and the passive film on the surface is easy to be damaged. Simultaneously, the corrosion effect promotes the growth of more pits, which leads to the concentration of local stress and the formation of more electrochemical cell. As a result, the mechanical and electrochemical corrosion factors are promoted. The synergetic effect accelerates the cavitation corrosion. The damage of cavitation corrosion reaches a maximum value at 55 ℃. Afterwards, the continuous increase of temperature improves the corrosion effect. However, the attenuation of impact strength of micro-jets weakens the destruction of surface passivation film. The mechanical effect plays a dominant role in cavitation erosion, accordingly the cavitation corrosion rate is mitigated.
Key words: Ti-6Al-4V alloy; lithium bromide solution; temperature; cavitation corrosion; influence mechanism
