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 inve...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 82 μm, 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.展开更多
Grain refining process plays a significant role in preventing columnar and coarse grains and it encourages fine grain formation. Although Al-Ti-B master alloys use widely as aluminium grain refiners, there are several...Grain refining process plays a significant role in preventing columnar and coarse grains and it encourages fine grain formation. Although Al-Ti-B master alloys use widely as aluminium grain refiners, there are several problems in their applications. So, this kind of master alloys use less than last. Because of great properties of Al-Ti-C refiners, they can be considered as suitable candidates for use instead of Al-Ti-B master alloys. In recent years, Al-Ti-C refiners have attracted huge attention among researchers. In this paper, Al-3Ti-1C master alloy is prepared with a melting reaction method. This method involves adding graphite powder and fine titanium particles into superheated pure aluminium. Then microstructure of this master alloy is studied by scanning electron microscope (SEM) and its phases are distinguished by energy dispersive spectroscopy (EDS). In the next part, 200 ppm of Al-3Ti-1C master alloy is added to pure aluminium and its refining efficiency is compared with the condition in which TiC powders are added to aluminium melt directly. It is found that the fading time for both Al-3Ti-1C and TiC powder is about 15 minutes and in overall, grain refining efficiency of Al-3Ti-1C is more than TiC powders in 60 minutes.展开更多
用专利方法制备出各种成分的Al Ti C中间合金作为铝及铝合金的晶粒细化剂。对该系列中间合金的组织和物相分析表明 :在制备中间合金过程中 ,C与Ti反应充分 ,生成TiC和TiAl3两种第二相 ,且TiAl3析出量取决于中间合金的Ti含量和Ti/C含量...用专利方法制备出各种成分的Al Ti C中间合金作为铝及铝合金的晶粒细化剂。对该系列中间合金的组织和物相分析表明 :在制备中间合金过程中 ,C与Ti反应充分 ,生成TiC和TiAl3两种第二相 ,且TiAl3析出量取决于中间合金的Ti含量和Ti/C含量比。用于纯铝的晶粒细化试验表明 :与Al Ti B中间合金相比 ,Al Ti C中间合金的晶粒细化效率更高 ;Al Ti C中间合金只有在组织中TiC与TiAl3保持适当比例时 ,才能对纯铝产生良好的晶粒细化效果 ,不含TiAl3的Al Ti C中间合金的晶粒细化作用很微弱 ;用Al Ti C中间合金细化纯铝晶粒时 ,响应时间短 ,但衰退较快 ,且不能通过熔体搅拌法予以消除。分析和探讨了Al Ti C中间合金的晶粒细化机理 ,认为“碳化物理论”不能充分解释Al Ti C的晶粒细化机理 ,提出“Ti在TiC或TiAl3颗粒表面富集引发包晶反应”的晶粒细化机制。展开更多
文摘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 82 μm, 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.
文摘Grain refining process plays a significant role in preventing columnar and coarse grains and it encourages fine grain formation. Although Al-Ti-B master alloys use widely as aluminium grain refiners, there are several problems in their applications. So, this kind of master alloys use less than last. Because of great properties of Al-Ti-C refiners, they can be considered as suitable candidates for use instead of Al-Ti-B master alloys. In recent years, Al-Ti-C refiners have attracted huge attention among researchers. In this paper, Al-3Ti-1C master alloy is prepared with a melting reaction method. This method involves adding graphite powder and fine titanium particles into superheated pure aluminium. Then microstructure of this master alloy is studied by scanning electron microscope (SEM) and its phases are distinguished by energy dispersive spectroscopy (EDS). In the next part, 200 ppm of Al-3Ti-1C master alloy is added to pure aluminium and its refining efficiency is compared with the condition in which TiC powders are added to aluminium melt directly. It is found that the fading time for both Al-3Ti-1C and TiC powder is about 15 minutes and in overall, grain refining efficiency of Al-3Ti-1C is more than TiC powders in 60 minutes.
文摘用专利方法制备出各种成分的Al Ti C中间合金作为铝及铝合金的晶粒细化剂。对该系列中间合金的组织和物相分析表明 :在制备中间合金过程中 ,C与Ti反应充分 ,生成TiC和TiAl3两种第二相 ,且TiAl3析出量取决于中间合金的Ti含量和Ti/C含量比。用于纯铝的晶粒细化试验表明 :与Al Ti B中间合金相比 ,Al Ti C中间合金的晶粒细化效率更高 ;Al Ti C中间合金只有在组织中TiC与TiAl3保持适当比例时 ,才能对纯铝产生良好的晶粒细化效果 ,不含TiAl3的Al Ti C中间合金的晶粒细化作用很微弱 ;用Al Ti C中间合金细化纯铝晶粒时 ,响应时间短 ,但衰退较快 ,且不能通过熔体搅拌法予以消除。分析和探讨了Al Ti C中间合金的晶粒细化机理 ,认为“碳化物理论”不能充分解释Al Ti C的晶粒细化机理 ,提出“Ti在TiC或TiAl3颗粒表面富集引发包晶反应”的晶粒细化机制。
