【作者】 张成华；

【导师】 蒋宗宇；

【作者基本信息】 江苏大学 ， 材料加工工程， 2003， 硕士

【摘要】 本文研究了ZA系合金中应用最广泛的ZA27合金，针对企业在工业应用过程中发现ZA27在中低速重载连续工作时，因温升造成耐磨性下降，难以满足工况要求的实际情况，为进一步提高其力学性能和高温耐磨性，结合国内外研究现状，在ZA27合金基础上，添加Si、Mn合金元素调整合金的组织，通过显微组织分析和常温机械性能测试，以探索ZnAlSi及ZnAlMn合金常温及高温滑动摩擦条件下的摩擦特性。 试验中，合金分别在中频感应炉和石墨坩埚电阻炉中熔炼。借助电子扫描显微镜、金相显微镜、电子探针显微分析仪等方法研究合金的显微组织，分析合金的性能。 试验结果表明，加Si的高铝锌基合金ZA27总体上硬度、抗拉强度均较高；Mn的加入有助于ZA27合金硬度的提高，加1.5％Mn时合金硬度最高；试验条件下，Mn的加入量超过0.8％时，其延伸率下降，在1.5％时达到最低值。适宜的加锰量为0.4-0.8％；在拉伸应力作用下加入Si或Mn后的ZA27，合金的断裂均为混合型断裂，既有塑性断裂，也有脆性断裂。裂纹主要始于脆性相Si相和Mn相，裂纹沿晶界扩展；在滑动摩擦条件下(常温)，含Si的ZA27合金在载重较小时，耐磨性与普通ZA合金相比没有明显提高，但在载荷较大的情况下，其耐磨性远高于普通ZA27合金材料；加Mn的ZA27合金与常规ZA27合金相比，耐磨性没有明显提高；在滑动摩擦条件下，Si的加入提高了ZA27合金的高温摩擦性能。Si的加入量为1％-3％时，ZA27合金的磨损量最少，高温摩擦性能最好；加入Mn后，ZA27合金在低温轻载下耐磨性能较好，高温耐磨性能不理想；在滑动摩擦条件下(高温)的磨损以粘着磨损和磨料磨损两种方式共同存在。更多还原

【Abstract】 ZA27 alloy-one of the most widely used ZA series alloys-is studied in this paper. In actual engineering applications, its wear resistance reduces due to the high temperature resulted from the continuous and heavy load service, which cannot fit the demand of engineering applications. Based on the recent research throughout the world, in order to improve mechanical properties and wear resistance at high temperature of ZA27 alloy, Si and Mn are added to modify its microstructure. Its microstructure and mechanical properties are tested and the sliding friction at ambient temperature and sliding friction at high temperature of ZnAlSi and ZnAIMn are studied.Alloys are melted in intermediate frequency furnace and Graphite crucible respectively. Si and Mn are alloyed to improve properties. Through SEM, metallographic microscope and Electronic probe microscopical analyzer, the microstructures of the alloy are studied and the properties are analyzed.Results show that the high aluminum zinc base alloy ZA27 alloyed by Si has an overall higher hardness and tensile strength; Mn can improve alloy’s hardness and at the same time reduce the elongation. When the content of Mn is 1.5wt. %, the hardness of the alloy is the highest but the elongation lowest. The premium content of Mn is about 0.4-0.8wt.%; Under the tensile stress, the fracture mode of ZA27 alloyed with Si or Mn is a mix type fracture- the plastic fracture and the brittle fracture are coexistence. Cracks are mainly stemmed from brittle phases of Si and Mn and develop along the grain boundary. When lightly loaded, the sliding friction resistance (at ambient temperature) of ZA27 alloyed with Si is no better than that of common ZA alloy. But when heavyly loaded, the former is far better than the latter. The wear resistance of ZA27 alloyed with Mn is no obviously better than that of common ZA27 alloy. Under the sliding friction conditions, the wear resistance at high temperature of ZA27 is improved by alloyed Si and reaches the highest level when the content of Si is 1-3wt.%. And also, the wear resistance at ambient temperature and of ZA27 alloyed with Mn when lightly loaded is desirable but becomes worse at high temperature. The wear mechanism of the one mixed with both adhesive and abrasive wear under sliding friction conditions (at high temperature).更多还原