The effects of grain refining parameters on grain size of AM60B magnesium alloy have been investigated using an Al-5Ti-IB master alloy as refiner; and an appropriate refining technique has been developed. The results ...The effects of grain refining parameters on grain size of AM60B magnesium alloy have been investigated using an Al-5Ti-IB master alloy as refiner; and an appropriate refining technique has been developed. The results indicate that the Al-Ti-B master alloy is an effective grain refiner for AM60B alloy and the grain size can be decreased from 348 μm to 76 μm. Raising the addition temperature or the poudng temperature is beneficial for grain refinement; while for the addition amount and holding time, there is an optimal value. The appropriate grain refining technique is that 0.3% Al-Ti-B master alloy is added at 780℃ and then the melt is held for 30 min before pouring. The above phenomena can be explained by the refining mechanisms that have been proposed from the related studies on Al and Mg alloys and theoretical analysis.展开更多
Nucleation sites of α-Al grains after addition of an Al-Ti-B master alloy into pure aluminium have been investigated using EPMA. The results show that either TiAl3 or boride particales can nucleate α-Al grains. But ...Nucleation sites of α-Al grains after addition of an Al-Ti-B master alloy into pure aluminium have been investigated using EPMA. The results show that either TiAl3 or boride particales can nucleate α-Al grains. But the number of TiAl3 nucleants is reduced with the holding time prolonged and the boride-nuclei are increasing gradually. Based on these results, a new refining method, adding molten Al-Ti-B into commercially pure aluminium, which has a quicker and better refining efficiency is presented.展开更多
Al-Ti-B-Er refiner was successfully prepared by CR （contact reaction process）, a process based on SHS （self propagating high-temperature synthesis）. The microstructure of the alloy was studied by optical microscop...Al-Ti-B-Er refiner was successfully prepared by CR （contact reaction process）, a process based on SHS （self propagating high-temperature synthesis）. The microstructure of the alloy was studied by optical microscopy, X-ray diffraction （XRD）, scanning electron microscopy （SEM） equipped with energy-dispersive spectrometry. The results showed that Al-Ti-B-Er alloy was composed of α-Al, block-like TiAl3 and flocked TiB2. Compared with Al-Ti-B refiner, formation of TiAlEr compounds, Er modified the morphology of TiAl3 phase, and dispersed the TiB2 and TiAl3. An excellent grain refining performance was obtained when adding 1 wt.% Al-Ti-B-Er in Al-10Zn-1.9Mg-1.6Cu-0.12Zr alloy, the average grain size was about 40 μm. The refinement mechanism of Al-Ti-B-Er was also discussed. Er changed the morphology of TiAl3, TiB2 phase, the refiner would be more efficient. The decomposition of TiAlEr compounds which released Er refrained the growth of TiAl3 and made TiB2 difficult to aggregate or deposit, therefore resulted in more particles being efficient nucleation substrate.展开更多
采用外加微量Al Ti B晶粒细化剂的方法以提高ZL210A强度塑性匹配的稳定性。结果表明:Al Ti B晶粒细化剂可以显著增加ZL210A合金在凝固过程中的形核核心,细化ZL210A合金的铸态及热处理后的组织,使ZL210A合金的强度及硬度较未添加晶粒细...采用外加微量Al Ti B晶粒细化剂的方法以提高ZL210A强度塑性匹配的稳定性。结果表明:Al Ti B晶粒细化剂可以显著增加ZL210A合金在凝固过程中的形核核心,细化ZL210A合金的铸态及热处理后的组织,使ZL210A合金的强度及硬度较未添加晶粒细化剂的合金提高5.3%及8.8%,伸长率可大幅提高232%。展开更多
基金financially supported by the National Basic Research Program of China (grant No.G2007CB613706)the Program for New Century Excellent Talents in University of China (grant No. NCET-10-0023)
文摘The effects of grain refining parameters on grain size of AM60B magnesium alloy have been investigated using an Al-5Ti-IB master alloy as refiner; and an appropriate refining technique has been developed. The results indicate that the Al-Ti-B master alloy is an effective grain refiner for AM60B alloy and the grain size can be decreased from 348 μm to 76 μm. Raising the addition temperature or the poudng temperature is beneficial for grain refinement; while for the addition amount and holding time, there is an optimal value. The appropriate grain refining technique is that 0.3% Al-Ti-B master alloy is added at 780℃ and then the melt is held for 30 min before pouring. The above phenomena can be explained by the refining mechanisms that have been proposed from the related studies on Al and Mg alloys and theoretical analysis.
文摘Nucleation sites of α-Al grains after addition of an Al-Ti-B master alloy into pure aluminium have been investigated using EPMA. The results show that either TiAl3 or boride particales can nucleate α-Al grains. But the number of TiAl3 nucleants is reduced with the holding time prolonged and the boride-nuclei are increasing gradually. Based on these results, a new refining method, adding molten Al-Ti-B into commercially pure aluminium, which has a quicker and better refining efficiency is presented.
基金supported by Beijing Municipal Natural Science Foundation(KZ20122100050008)National Basic Research Program of China(2012CB6198503)
文摘Al-Ti-B-Er refiner was successfully prepared by CR （contact reaction process）, a process based on SHS （self propagating high-temperature synthesis）. The microstructure of the alloy was studied by optical microscopy, X-ray diffraction （XRD）, scanning electron microscopy （SEM） equipped with energy-dispersive spectrometry. The results showed that Al-Ti-B-Er alloy was composed of α-Al, block-like TiAl3 and flocked TiB2. Compared with Al-Ti-B refiner, formation of TiAlEr compounds, Er modified the morphology of TiAl3 phase, and dispersed the TiB2 and TiAl3. An excellent grain refining performance was obtained when adding 1 wt.% Al-Ti-B-Er in Al-10Zn-1.9Mg-1.6Cu-0.12Zr alloy, the average grain size was about 40 μm. The refinement mechanism of Al-Ti-B-Er was also discussed. Er changed the morphology of TiAl3, TiB2 phase, the refiner would be more efficient. The decomposition of TiAlEr compounds which released Er refrained the growth of TiAl3 and made TiB2 difficult to aggregate or deposit, therefore resulted in more particles being efficient nucleation substrate.
文摘采用外加微量Al Ti B晶粒细化剂的方法以提高ZL210A强度塑性匹配的稳定性。结果表明:Al Ti B晶粒细化剂可以显著增加ZL210A合金在凝固过程中的形核核心,细化ZL210A合金的铸态及热处理后的组织,使ZL210A合金的强度及硬度较未添加晶粒细化剂的合金提高5.3%及8.8%,伸长率可大幅提高232%。
