(1. 合肥工業(yè)大學 機械工程學院 摩擦學研究所，合肥 230002；
2. 合肥熠輝輕合金科技有限公司，合肥 230088)
摘 要: 采用正交試驗法分析了液態(tài)模鍛Al-Sn-Cu軸套中Sn的宏觀偏析規(guī)律。結果表明：液態(tài)模鍛Al-Sn-Cu軸套不可避免的產(chǎn)生Sn的宏觀偏析，鑄件中同時存在著正偏析和逆偏析，正偏析出現(xiàn)在澆鑄中心的近端，逆偏析主要存在于澆鑄中心的遠端；鑄件凝固后期，低熔點液相被強制擠壓至熱節(jié)位置，形成粗晶區(qū)和細晶區(qū)相間的雙峰組織，細晶區(qū)Sn的質量分數(shù)明顯較高。液態(tài)模鍛工藝參數(shù)對鑄件宏觀偏析產(chǎn)生較大影響，對Sn偏析影響由大到小依次是澆注溫度、模具溫度、保壓時間及比壓；本次實驗條件下，當澆注溫度為700 ℃，模具溫度為240 ℃，比壓為80 MPa，保壓時間為5 s時，軸套鑄件中Sn元素分布較均勻，Sn元素的宏觀偏析得到減輕。
關鍵字: 正交試驗法；液態(tài)模鍛；Al-Sn-Cu；雙峰組織；宏觀偏析
（1. Institute of Tribology, School of Mechanical Engineering, Hefei University of Technology, Hefei 230002, China;
2. Hefei Yihui Light Alloy Technology Co., Ltd., Hefei 230088, China）
Abstract:Orthogonal test was used to investigate the macrosegregation of Sn in Al-Sn-Cu sleeve in the squeeze casting. The results show that the macrosegregation of Sn is inevitable in Al-Sn-Cu sleeve in the squeeze casting. In the casting, both positive segregation and inverse segregation exist. The positive segregation appears near the casting center, while the reverse segregation mainly exists at the far end of the casting center. At the later solidification stage, the liquid phase with low melting point is forced to be extruded to the thermal center, which formed bimodal structure of coarse crystal region and fine crystal region, and the Sn mass fraction of fine crystal region was obviously higher. The process parameters have a great influence on the macrosegregation of castings. The influence sequence of squeeze casting parameters on macrosegregation from large to small is pouring temperature, die temperature, dwell time and specific pressure. Under this experiment condition, the distribution of Sn element in shaft sleeve casting is uniform and the macrosegregation of Sn element is reduced, when the pouring temperature is 700 ℃, mold temperature is 240 ℃, the pressure is 80 MPa, the holding time is 5 s.
Key words: orthogonal experiment; squeeze casting; Al-Sn-Cu; bimodal structure; macrosegregation
