电刷镀—激光复合强化铝基模具材料表面性能试验研究

发布时间：2018-08-13 16:46

【摘要】：铝基模具在机械加工领域具有重要的应用比例。其表面在应用过程中经常会出现不同程度的磨损、断裂等失效现象,影响模具的使用效率和工作寿命。尤其是磨损失效中的表面粘附程度严重影响着产品的表面质量。因此,降低模具材料表面的粘附作用是提高工作效率和产品质量的重要措施。本文通过分析模具材料表面的失效机理,利用荷叶和水稻叶表面的特殊功能特性所给予的灵感,基于润湿性理论对模具材料表面的粘附问题进行初步探讨。选用7075号铝合金模具材料作为试验基体材料,利用电刷镀技术在光滑基体表面均匀覆盖一定厚度的镍镀层,金属镍镀层的存在使表面的抗腐蚀能力提高1个数量级,表面硬度由基体96.4HV提高至400HV,但此时的表面表现出较强的粘附作用。为此,试验将具有良好耐腐蚀的镍镀层表面进一步进行激光扫描加工。在电刷镀-激光结合的复合加工方法作用下,“菜花状”的凸包与沟槽的配合分布构成表面的微观复合结构。这种特殊的非光滑表面能够在微观结构内部存储更多的外界空气,在加工表面形成一层气体薄膜,有效降低固体表面与外来物体的直接接触。从润湿性的角度降低了表面的粘附程度,使铝合金模具材料表面与产品之间的脱模过程变得更加顺利成为可能,从而降低模具表面粘模问题发生的机率。进一步研究发现,电刷镀-激光结合方法的应用,还能够赋予材料表面优异的耐腐蚀性能,抗腐蚀能力提高2~3个数量级,这为提高模具材料表面的综合性能提供了一定的试验参考价值。
[Abstract]:Aluminum-based die has an important application ratio in the field of mechanical processing. In the process of application, failure phenomena such as wear and fracture often occur on the surface, which affect the efficiency and service life of the die. Especially, the surface adhesion in wear failure seriously affects the surface quality of products. Therefore, it is an important measure to improve the working efficiency and product quality to reduce the adhesion on the surface of die materials. Based on the theory of wettability, this paper analyzes the failure mechanism of mould material surface, and discusses the adhesion problem of mould material surface based on the special functional characteristics of lotus leaf and rice leaf surface. The 7075 aluminum alloy mould material was selected as the base material of the test. The nickel coating was uniformly covered on the smooth substrate by brush plating technology. The corrosion resistance of the surface was improved by one order of magnitude because of the presence of the metal nickel coating. The surface hardness was increased from matrix 96.4HV to 400HV, but the surface exhibited strong adhesion at this time. Therefore, the surface of nickel coating with good corrosion resistance will be further processed by laser scanning. Under the combined processing method of brush plating and laser, the distribution of the convex hull and the groove of "cauliflower" formed the microstructure of the surface. This special non-smooth surface can store more external air in the microstructure and form a layer of gas film on the machined surface which can effectively reduce the direct contact between the solid surface and foreign objects. The adhesion degree of the surface is reduced from the point of wettability, which makes it possible for the process of demoulding between the surface of the aluminum alloy die material and the product to become more smooth, thus reducing the probability of the die sticking problem on the surface of the die. It is further found that the application of brush plating combined with laser method can also give excellent corrosion resistance to the surface of the material, and the corrosion resistance can be increased by 2 to 3 orders of magnitude. This provides a certain reference value for improving the comprehensive properties of die material surface.
【学位授予单位】：长春理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ153.12

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