(华南理工大学 材料科学与工程学院，广州 510640)
摘 要: 利用普通铸造法制备不同Sr含量的ZA35-4Si-3Sn合金，研究Sr含量对该合金凝固组织和拉伸力学性能的影响，并揭示影响机制，探讨Sr变质合金的摩擦磨损特性。结果表明：Sr含量为0.1%(质量分数)时，初生硅趋向于球状，细小的颗粒状或纤维状共晶硅数量显著增加；此时，合金的硬度达到143HBW，抗拉强度与拉伸应变分别提高45.8%和151.5%。Sr变质主要为促进共晶硅相形核和抑制共晶硅相的生长两种机制共同作用的结果。与ZA27合金相比，ZA35-4Si-3Sn-0.1Sr合金具有更低的摩擦因数。在低速磨损条件下，两种合金的耐磨性相当；而在高速下，后者具有更低的摩擦温升和磨损量，表现出优异的摩擦磨损特性。
关键字: 耐磨锌合金；Sr变质；热分析法；摩擦；磨损
（School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, China）
Abstract:ZA35-4Si-3Sn alloy containing with different Sr contents were prepared by ordinary gravity casting. The effect of Sr content on the microstructure and tensile strength were investigated. The modification mechanism of Sr was deeply disclosed through thermal analysis. The dry sliding friction and wear properties under different sliding speeds were mainly studied. The results show that the primary Si crystals gradually become nodular, while the eutectic Si crystals with fine fibrous structure significantly increase with increasing the Sr content. After being modified by 0.1%Sr (mass fraction), the hardness of ZA35-4Si-3Sn alloy increases to 143 HB. The tensile strength and strain to failure are improved by about 45.8% and 151.5%, respectively. The modification mechanism is mainly ascribed to promote the nucleation and restrict the growth of eutectic Si crystals. Compared with ZA27 alloy, ZA35-4Si-3Sn-0.1Sr possesses lower friction coefficient. There is no significant change in wear properties under the low sliding speed of 200 r/min. However, the ZA35-4Si-3Sn-0.1Sr exhibits excellent friction and wear properties under high sliding speed of 400 r/min with lower temperature rising and wear loss.
Key words: wear-resistant zinc alloy; strontium modification; thermal analysis; friction; wear
