共查询到19条相似文献,搜索用时 140 毫秒
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深过冷定向凝固工艺过程的研究 总被引:3,自引:0,他引:3
利用过冷度的遗传性,提出了将合金熔体深过冷与传统定向凝固相结合的深过冷定向凝固技术,并在自制的实验装置上,对SDS技术进行了探索性研究,实现了Cu与w(Ni)为5.0%合金的深过冷和深过冷定向凝固。 相似文献
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基于平面流铸快速凝固过程的牛顿冷却方式假定和过冷熔体中的枝晶生长理论,提出了凝固相重量分数计算的物理模型和数学计算方法。该模型可对快速凝固过程中不同相的过冷度,晶体的生长速度以及最终的相组成进行半定量的计算和预测。Ni31.5Al68.5合金条带的快速凝固过程的计算结果和试验测定数据有较好的吻合。 相似文献
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基于平面流铸快速凝固过程的牛顿冷却方式假定和过冷熔体中的枝晶生长理论 ,提出了凝固相重量分数计算的物理模型和数学计算方法。该模型可对快速凝固过程不同相的过冷度、晶体的生长速度以及最终的相组成进行半定量的计算和预测。Ni3 1 5Al68 5合金条带的快速凝固过程的计算结果和试验测定数据有较好的吻合。 相似文献
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新型真空熔化定向凝固装置原理研究 总被引:3,自引:0,他引:3
对真空感应熔炼与双区加热结合在一起的定向凝固装置进行了可行性研究,并研制出了一套新型真空熔化定向凝固装置,该装置兼有熔炼和定向凝固的功能,熔炼好的合金液能自动底注到定向炉内的型壳中,定向凝固部分采用了先进了双区加热技术,定向凝固结晶生长速率能在很大范围内调节。 相似文献
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In the comparison of the solidification characteristics of supercooling directional solidification (SDS) with constrained directional solidification (DS) and with the consideration of the inheritance of supercooled melt, the SDS technique established with the combination of melt supercooling and traditional DS was proposed. An exploring study on SDS techniques was also conducted using appropriate facilities, designed and manufactured by the authors’ laboratory and the deep supercooling of Cu–5.0%Ni alloy, and its DSs were implemented. 相似文献
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钛铝合金是性能优异的高温合金,在航空航天领域有广泛的应用前景,但由于其熔体具有较高的活性,制备时熔体与所有已知的铸型材料会发生不同程度的反应,限制了钛铝合金铸件的发展.定向凝固技术作为制备高精度钛铝合金的新工艺,使铸件组织定向排列,可以进一步提高钛铝合金的使用性能,因此如何调控凝固过程中钛铝合金熔体与铸型材料间的界面反应成为目前有关定向凝固钛铝合金研究的一个热点.从目前国内外关于钛铝合金熔体与铸型材料间界面反应的研究出发,综述了定向凝固过程中铸型材料、涂层成分、工艺参数及合金元素等对界面反应的影响,介绍了界面反应的理论水平,系统收集了界面反应的各项研究结果. 相似文献
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Hongqun Zhu Yajun Tang Yingao Li Yaoxiao Zhu Zhuangqi Hu Changxu Shi 《Materials at High Temperatures》2013,30(1):39-44
The effect of boron and zirconium on the directional solidification behaviour and segregation of IN738 superalloy has been studied. It was found that additions of boron and zirconium enlarge the solidus-liquidus temperature interval and increase the amount of residual melt during solidification. Boron gives the alloy a tendency to form developed dendrites, while zirconium enhances a cellular solidified structure. Both boron and zirconium are shown to be rejected to the residual melt during solidification, and shown to change the segregation of alloying elements by interaction. 相似文献
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Jie He Chengyao Xing Jiuzhou Zhao Lei Zhao Institute of Metal Research Chinese Academy of Sciences Shenyang China 《材料科学技术学报》2010,26(2):136-140
The directional solidification has been carried out for the Al-4Bi-2.5Co (wt pct) alloys with different melt superheat temperatures. The microstructure characterization and the quantitative metallographic analysis have been performed. The results indicated that the Bi-rich sphere size and cellular spacing decrease with increasing melt superheat temperature. The interaction between the advancing solidification interface and the Bi-rich spheres with different sizes was analyzed. The effect of the melt superheat treatment on microstructure evolution was discussed for the immiscible alloys. The microstructure development in ternary Al-Bi-Co alloys directionally solidified with different melt superheat temperatures was clarified. 相似文献
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Compared with the growing applications of peritectic alloys,none research on the fluid permeability K of dendritic network during peritectic solidification has been reported before.The fluid permeability K of dendritic network in the mushy zone during directional solidification of Sn-Ni peritectic alloy was investigated in this study.Examination on the experimental results demonstrates that both the temperature gradient zone melting (TGZM) and Gibbs-Thomson (G-T) effects have obvious influences on the morphology of dendritic network during directional solidification.This is realized through different stages of liquid diffusion within dendritic mushy zone by these effects during directional solidification.The TGZM effect is demonstrated to play a more important role as compared with the G-T effect during directional solidification.Besides,it is shown that the evolution of dendrite network is more complex during peritectic solidification due to the involvement of the peritectic phase.Through the specific surface Sv,analytical expression based on the Carman-Kozeny model was proposed to analyze the fluid permeability of dendritic mushy zone in directionally solidified peritectic alloys.In addition,it is interesting to find a rise in permeability K after peritectic reaction in both theoretical predication and experimental results,which is different from that in other alloys.The theoretical predictions show that this rise in fluid permeability K after pedtectic reaction is caused by the remelting/resolidification process on dendritic structure by the TGZM and G-T effects during peritectic solidification. 相似文献
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温度梯度对定向凝固Al-4.5%Cu合金一次枝晶间距的影响 总被引:1,自引:0,他引:1
使用5kg坩埚下拉式定向凝固设备,对Al-4.5%Cu合金进行定向凝固试验,研究Al-4.5%Cu合金在不同温度梯度下一次枝晶间距的变化规律。结果表明:在其他凝固参数不变时,随着温度梯度的增大,一次枝晶逐渐变小,细密,挺直,基本呈平行状分布,同时计算的一次枝晶间距值与Hunt模型计算值接近,实验测得的一次枝晶间距的回归曲线为:y=2843478.3x2-70217.4x+543.8。用温度梯度较高的实验值来模拟时,可得到1λ=26.7G-0.5-135.9,一次枝晶间距λ1与G-0.5基本呈线性关系,这和Hunt模型分析结果一致。 相似文献