(1. 重慶工程職業(yè)技術學院 機械工程學院，重慶 400037；
2. 徐工集團 工程機械股份有限公司，徐州 221004；
3. 重慶大學 材料科學與工程學院，重慶 400030)
摘 要: 采用離心鑄造方法在不同工藝條件下制備Al-9Ni-15Si復合材料筒狀零件，研究不同工藝成形鑄件沿徑向方向和垂直于軸向方向的微觀組織特征，測試不同工藝成形鑄件的硬度及耐磨性能。結果表明：Al-9Ni-15Si復合材料鑄件形成了外層聚集了大量自生初生Al3Ni/Si顆粒、內(nèi)層含有較多的初生Si/Al3Ni顆粒以及中間層不含顆粒的3層組織。隨著澆注溫度和模具溫度的升高，鑄件外、內(nèi)層顆粒的體積分數(shù)逐漸增加，其硬度值逐漸增大，而體積磨損量逐漸減少。在離心場中，Al3Ni的離心運動和Si的向心漂移是形成Al-9Ni-15Si復合材料3層組織的主要原因；而澆注溫度和模具溫度越高，合金的凝固時間越長，越有利于形成高體積分數(shù)的顆粒偏聚區(qū)，從而提高復合材料的力學性能。
關鍵字: Al-9Ni-15Si復合材料；初生Al3Ni/Si；硬度；耐磨性；離心鑄造；顯微組織；性能
（1. College of Mechanical Engineering, Chongqing Vocational Institute of Engineering, Chongqing 400037, China;
2. Xuzhou Construction Machinery Group, Construction Machinery Co., Ltd., Xuzhou 221004, China;
3. College of Materials Science and Engineering, Chongqing University, Chongqing 400030, China）
Abstract:The Al-9Ni-15Si composite tubes were prepared under different conditions by centrifugal casting. Along the radial direction and the direction perpendicular to the axial direction of the castings, the microstructure characteristics were investigated, and their hardness and wear resistance were measured. The results show that Al-9Ni-15Si composite castings form a three-layer microstructure including a large number of in-situ primary Al3Ni/Si particles in the outer layer, many primary Si/Al3Ni particles in the inner layer and few particles in the middle layer. As the pouring and mould temperatures increase, the particle volume fractions of the outer and inner layers gradually increase, the hardness values on those zones increase as well, while the volume frictions of them gradually reduce. In the centrifugal field, the centrifugal movement of Al3Ni and the centripetal drift of Si are the main reasons for the formation of the Al-9Ni-15Si composite with three layers. The higher the pouring and mold temperatures are, the longer the solidification time is, and the more beneficial to the formation of high volume fraction particle area is, thus improving the mechanical properties of the composite.
Key words: Al-9Ni-15Si composite; primary Al3Ni/Si; hardness; wear resistance; centrifugal casting; microstructure; property
