基于COMSOL的微弧氧化过程温度场分布研究

发布时间：2019-01-30 15:23

【摘要】：目的研究微弧氧化过程的温度场分布情况对成膜过程及表面形貌的影响。方法以7075铝合金微弧氧化过程中的一个放电通道为研究对象,基于多物理场仿真软件COMSOL Mutiphysics建立了微弧氧化传热过程的数学模型及物理模型。基于有限元法求解出微弧氧化成膜过程的温度场分布,选择特定参考线及参考点,绘制了温度-时间曲线。选择0、100、500、1000μs四个关键时间点,绘制了对应的温度-纵向深度曲线、温度分布云图及温度梯度分布云图,并探究其对陶瓷层表面形貌的影响。结果在0~100μs时,放电通道区域温度下降速率最快;在100~500μs时,温度下降速率逐渐减小;在500~1000μs时,温度下降速率最小且趋于不变。相对于放电通道中心区域,靠近氧化铝膜层-铝合金基体界面区域温度下降速率较快,温度梯度较大;在0、100、500、1000μs时,最高温度所在位置的纵向深度依次为93、20、26、38μm,呈现先减小后增大的趋势。结论电解液对微弧氧化过程的冷却作用主要集中于放电通道形成后的100μs内。除电解液外,氧化铝膜层-铝合金基体界面在微弧氧化成膜过程中有一定的冷却作用,而放电通道各区域冷却速率不均衡是氧化膜表面形成火山口状孔洞的主要原因。
[Abstract]:Aim to study the effect of temperature field distribution on film formation and surface morphology in the process of micro-arc oxidation. Methods based on a discharge channel of 7075 aluminum alloy during micro-arc oxidation, a mathematical model and a physical model of micro-arc oxidation heat transfer process were established based on the multi-physical field simulation software COMSOL Mutiphysics. Based on the finite element method, the temperature field distribution in the process of micro-arc oxidation film formation is solved, and the temperature-time curve is drawn by selecting the specific reference line and reference point. The temperature longitudinal depth curve, temperature distribution cloud diagram and temperature gradient distribution cloud diagram were drawn at four key time points of 0: 100 ~ 500 渭 s and 1000 渭 s, and the influence of them on the surface morphology of ceramic coatings was investigated. Results the temperature drop rate in the discharge channel was the fastest at 0 ~ 100 渭 s, decreased gradually at 100 ~ 500 渭 s, and decreased at 500 ~ 1000 渭 s, the temperature drop rate was the smallest and tended to be constant at 500 ~ 1000 渭 s. Compared with the central region of the discharge channel, the temperature drop rate is faster and the temperature gradient is larger in the area near the interface between the aluminum oxide film and the aluminum alloy substrate. The longitudinal depth of the highest temperature is 93o 20 ~ 2638 渭 m, which decreases at first and then increases when the maximum temperature is at 1000 渭 s. Conclusion the cooling effect of electrolyte on the microarc oxidation process is mainly within 100 渭 s after the discharge channel is formed. In addition to electrolyte, the interface between alumina film and aluminum alloy substrate has a certain cooling effect in the process of micro-arc oxidation film formation, and the uneven cooling rate in different regions of discharge channel is the main reason for the formation of crater hole on the surface of oxide film.
【作者单位】：烟台大学机电汽车工程学院;海军航空工程学院基础实验部;
【基金】：国家自然科学基金资助项目(51405416) 山东省自然科学基金资助项目(ZR2014EEQ024) 山东省科技发展计划(2012YD15010)~~
【分类号】：TG174.45

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