烧结温度对碳化钨增强铜基粉末冶金摩擦材料性能的影响规律研究

Effect of Sintering Temperature on Properties of WC Reinforced Cu-Based Powder Metallurgical Friction Materials

摘要:

铜基粉末冶金摩擦材料因优异的耐磨性、导热性、抗粘结性及高承载能力，作为制动材料被广泛应用于高速列车、航天飞机、船舶等的制动系统中。随着高速列车运行速度的不断提高，对铜基粉末冶金刹车材料的耐磨性、耐热性及摩擦稳定性提出了更高的要求，通过改良刹车材料的组元配比及制备工艺提高其摩擦稳定性已成为材料领域的研究重点。采用粉末冶金法，在不同烧结温度(850、900、950和1 000 ℃)下制备球形碳化钨（WC）增强铜基粉末冶金摩擦材料，并对其致密度、硬度、摩擦学性能及显微组织结构进行了系统的研究。采用阿基米德排水法测定材料的实际密度和孔隙率，通过布氏硬度计、摩擦磨损试验机和扫描电镜等对材料的硬度、摩擦磨损性能及显微组织进行表征与分析。结果表明：不同烧结温度下WC颗粒呈球状均匀地镶嵌于基体中，且与基体结合紧密；随着烧结温度的升高，WC增强铜基粉末冶金摩擦材料密度及硬度降低、孔隙率升高。在温度850—950 ℃范围内，摩擦材料的摩擦磨损性能持续提升，当烧结温度超过950 ℃后，材料的摩擦磨损性能下降。WC增强铜基粉末冶金摩擦材料的最佳烧结温度为950 ℃，此时的密度为5.51 g?cm^-3、孔隙率为7.8%、硬度为22.8 HB、摩擦系数为0.41、磨损量为8.1 mg。通过研究烧结温度对WC增强铜基摩擦材料微观组织及摩擦学性能的影响规律，为新型高性能高速列车用Cu基摩擦材料的成分优化及制备工艺改进提供了理论基础和实验依据。(专精特新·特殊环境材料服役行为专辑十五之十四)

Abstract:

Cu-based powder metallurgy （P/M） friction materials exhibit excellent wear resistance， thermal conductivity， adhesion resistance， high load-bearing capacity and stable performance， making them widely used in high-speed trains， space shuttles， ships， and other brake systems. As train speeds continue to increase， higher demands are placed on the wear and heat resistance of Cu-based P/M brake materials. Enhancing friction stability by optimizing material composition and fabrication processes remains a key research focus. In this study， spherical tungsten carbide （WC）-reinforced Cu-based P/M friction materials were fabricated at different sintering temperatures （850， 900， 950， 1 000 ℃） using powder metallurgy. The Archimedes drainage method was employed to measure density and porosity， while hardness， friction and wear properties and microstructural characteristics were analyzed using a Brinell hardness tester， friction and wear tester and scanning electron microscope. The results show that WC particles are uniformly distributed， embedded in a spherical form within the sintered Cu matrix， and exhibit strong interfacial bonding. As the sintering temperature increases， material density decreases， porosity rises， and hardness declines. The friction and wear properties improve with increasing sintering temperature up to 950 ℃ but deteriorate at higher temperatures. The optimal sintering temperature is determined to be 950 ℃， at which the material achieves a density of 5.51 g?cm^-3， a porosity of 7.8%， a hardness of 22.8 HB， a friction coefficient of 0.41， and a wear loss of 8.1 mg. This study provides theoretical and experimental insights for optimizing the composition design and manufacturing process of high-performance Cu-based friction materials for high-speed trains.