纳米TiN/Ti复合细化剂对工业纯铝铸态及热加工态组织的影响

摘要

采用高能球磨法制备一种纳米TiN/Ti复合晶粒细化剂，研究该细化剂对工业纯铝的铸态及热加工态组织的影响。结果表明：TiN/Ti复合细化剂对工业纯铝具有明显的晶粒细化作用，当TiN/Ti复合细化剂添加量为0.2%时(质量分数)，平均晶粒尺寸细化至82μm，其细化效果优于纯Ti和Al−5Ti−1B中间合金。添加0.1% TiN/Ti纯铝铸锭的焊缝组织以细小的等轴晶为主，焊缝硬度明显高于母材。冷变形量为40%的纯铝铸锭于250°C下再结晶处理1.0 h后，添加0.1%Ti粉的试样晶粒长大较为明显。而添加0.1%TiN/Ti的试样，因变形导致的晶粒变形已消除，晶粒没有明显增粗，表明细化剂中的纳米TiN可抑制再结晶过程中的晶粒长大。%A novel type nano TiN/Ti composite grain refiner (TiN/Ti refiner) was prepared by high energy ball milling, and its effect on as-cast and hot-working microstructure of commercial purity aluminum (pure Al) was investigated. The results show that TiN/Ti refiner exhibits excellent grain refining performances on pure Al. With an addition of 0.2%TiN/Ti refiner, the average grain size of pure Al decreases to 82μm, which is smaller than that of pure Ti and Al−5Ti−1B master alloy as refiners. The microstructure of weld joint of pure Al with 0.1%TiN/Ti refiner is fine equiaxed grains and the hardness of weld joint is higher than that of the base metal. For pure Al with 40%cold deformation and recrystallization at 250 °C for 1.0 h, the grains of the sample added 0.1%Ti powder have an obvious grain growth behavior. In contrast, oriented grains caused by deformation have been eliminated, and there is no obvious grain growth in pure Al refined with 0.1%TiN/Ti refiner, indicating that nano TiN in the refiner inhibits the growth of grain during recrystallization.