(華南理工大學(xué) 材料科學(xué)與工程學(xué)院，廣州 510640)
摘 要: 利用普通鑄造法制備不同Sr含量的ZA35-4Si-3Sn合金，研究Sr含量對(duì)該合金凝固組織和拉伸力學(xué)性能的影響，并揭示影響機(jī)制，探討Sr變質(zhì)合金的摩擦磨損特性。結(jié)果表明：Sr含量為0.1%(質(zhì)量分?jǐn)?shù))時(shí)，初生硅趨向于球狀，細(xì)小的顆粒狀或纖維狀共晶硅數(shù)量顯著增加；此時(shí)，合金的硬度達(dá)到143HBW，抗拉強(qiáng)度與拉伸應(yīng)變分別提高45.8%和151.5%。Sr變質(zhì)主要為促進(jìn)共晶硅相形核和抑制共晶硅相的生長(zhǎng)兩種機(jī)制共同作用的結(jié)果。與ZA27合金相比，ZA35-4Si-3Sn-0.1Sr合金具有更低的摩擦因數(shù)。在低速磨損條件下，兩種合金的耐磨性相當(dāng)；而在高速下，后者具有更低的摩擦溫升和磨損量，表現(xiàn)出優(yōu)異的摩擦磨損特性。
關(guān)鍵字: 耐磨鋅合金；Sr變質(zhì)；熱分析法；摩擦；磨損
（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
