激光熔覆灰铸铁制动盘Fe-Ni-Cr梯度复合涂层微观组织及高温摩擦磨损性能研究  

Microstructures and High-Temperature Friction and Wear Properties of Laser Cladded Fe-Ni-Cr Gradient Composite Coating for Brake Disc

作　　者：时晓宇 温道胜 王守仁[1] 王高琦 张明远 Shi Xiaoyu;Wen Daosheng;Wang Shouren;Wang Gaoqi;Zhang Mingyuan(School of Mechanical Engineering,University of Jinan,Jinan,Shandong 230022,China)

机构地区：[1]济南大学机械工程学院,山东济南250022

出　　处：《中国激光》2022年第2期182-193,共12页Chinese Journal of Lasers

基　　金：国家自然科学基金(51872122);山东省自然科学基金重大基础研究项目(ZR2020ZD06);山东省自然科学基金重点项目(ZR2020KE062);泰山学者工程专项资助项目(ts201511040);济南市自主创新团队资助项目(2019GXRC012)。

摘　　要：激光熔覆是解决灰铸铁制动盘磨损失效的一种可靠办法,但灰铸铁中存在的片状石墨会影响涂层的质量,降低涂层与基体的结合强度。本研究团队在灰铸铁制动盘表面熔覆了Fe-Ni-Cr复合涂层,并对涂层的相组成、显微组织、硬度及耐磨性能进行了分析。结果表明:涂层中的物相主要为Fe;C;和Fe;C,而且这些物相呈阶梯状分布;涂层与基体结合良好,且熔覆区晶体的生长形态由柱状晶逐渐转变为胞状晶、枝状晶和等轴晶;在晶粒细化的作用下,涂层硬度略有波动,其平均硬度为468 HV0.3;涂层的耐磨性优于基体;随着试验温度由100℃升高到300℃,涂层的磨损量逐渐减少,涂层的磨损机理逐渐从以磨粒磨损为主转变为以黏着磨损和氧化磨损为主;当试验温度为300℃时,涂层的磨损量最小。Objective The brake disc, as a consumable component of the braking system, has a typical service life of 50 to 80 thousand kilometers. If the brake disc is severely worn, the difference between the actual and expected braking distances will be too great, affecting driving maneuverability and safety. At present, the brake disc is mainly cast with gray cast iron as raw material. However, gray cast iron performs poorly in terms of wear resistance and hightemperature resistance. Laser cladding, as a new surface modification technology, can be used to create coatings that meet the service requirements of various working conditions. Fe-Ni-Cr alloy has an excellent thermal expansion coefficient, which can meet the needs of the brake disc in a high-temperature environment. Currently, some researchers have used Fe-Ni-Cr alloys, but they did not achieve good results on gray cast iron. The main reason for this is that gray cast iron contains a lot of flocculent graphite, and there are gaps and inclusions between these graphite components and the substrate during the casting process. It is more difficult to modify the surface of laser cladding gray cast iron. In this paper, Fe-Ni-Cr composite coating was prepared on the surface of gray cast iron by laser cladding technology. The graphite component of gray cast iron is combined with the powder component of the coating material to form a phase that matches the properties of the substrate material and displays a gradient distribution in the coating. Consequently, the bonding strength can be increased without affecting the coating’s properties.Methods Gray cast iron was selected as the test substrate. Before the laser cladding test, the oxide layer on the surface of the substrate was sanded and cleaned with an ultrasonic cleaning machine in an alcohol environment for 15 min, then the substrate was dried and stored for testing. Chose powder with diameter of 50-100 μm as cladding powder and mix it in a planetary ball mill for 2 h. Laser cladding tests were carried out in LAM-40

关 键 词：激光技术 激光熔覆 制动盘 微观组织 摩擦磨损 

分 类 号：TG174.44[金属学及工艺—金属表面处理]