熔体状态对B83巴氏合金凝固组织和摩擦性能的影响

Effects of Melt State on Solidification Microstructure and Tribological Properties of B83 Babbitt Alloy

探索了升降温过程B83巴氏合金液体的电阻率温度行为（ρ-T）,继而根据所揭示的熔体状态随温度改变的信息,研究了不同熔体状态对凝固行为、凝固组织形貌和摩擦性能的影响。B83熔体ρ-T行为提示,合金液在首轮升温过程的779~1 001℃范围存在不可逆的熔体状态转变,且在后续升降温过程中,在720℃左右存在可逆熔体状态转变。凝固实验表明,经历了不可逆熔体状态转变的熔体开始凝固形核时间滞后,在凝固过程每一阶段的过冷度都有所增大,且在坩埚空冷和铜管冷却条件下凝固组织明显细化,分布更为均匀。检测表明,组织的改变提高了B83合金维氏硬度,还使其具有更好的摩擦特性。这些结果对巴氏合金制备方法的创新及提高服役性能具有积极意义,同时也再次证明,藉熔炼温度调控熔体结构状态,可有效改善合金凝固组织与性能。

In this study, the liquid resistivity-temperature（p-T） behavior of B83 babbitt alloy during heating and cooling temperature was explored. Based on the information and revealed by the change of melt state with temperature, the effects of different melt state on solidification behavior, microstructure and tribological properties were investigated. Thep-T of the B83 melt inferred that an irreversible melt state transition within the temperature range of 779-1 001 ℃ existed in the first heating process and a reversible melt state transition at about 720 ℃ occurred in following heating and cooling process. The solidification experiments indicated that the start nucleation time of the melt which experienced the irreversible melt state transition was retardant and its undercooling was enlarged in each solidification stage. Also, the solidification microstructure was refined and distributed more uniformly, whatever cooling in air or cooper tube. Test results show that the changed microstructure improved the Vickers hardness of B83 and made it has better tribological properties. These results had positive implications for the innovation on babbitt preparation methods and improving performance on service. And they verified again that the properly controlling melt state by smelting temperature could effectively improve the alloy solidification microstructure and its properties.