论文部分内容阅读
目的了解Nb-16Si-2Fe合金热变形的高温力学行为,并掌握其变形过程中的组织演变。方法采用真空非自耗电弧炉制备了Nb-16Si-2Fe合金,利用Gleeble-1500热模拟机对合金进行高温压缩实验,并通过XRD对合金相结构进行分析。结果合金由白色树枝晶状Nbss固溶体相、灰色连续基体Nb3Si相及黑色块状Nb4Fe Si相组成。试样在较低温度、较大变形速率压缩时,产生脆性断裂。在1200~1400℃范围内,随着变形温度的升高及变形速率的降低,试样开裂倾向减小,应力峰值降低。脆性Nb3Si相由连续分布变成孤岛状分布,并发生共析反应分解生成细小两相组织。结论高温压缩过程使硬脆相Nb3Si含量降低,韧性相Nbss相含量增加,合金高温强度下降,一定程度上降低了该合金的塑性加工难度。
Objective To understand the high-temperature mechanical behavior of Nb-16Si-2Fe alloy during hot deformation and to understand the microstructure evolution during the deformation process. Methods The Nb-16Si-2Fe alloy was prepared by vacuum non-consumable electric arc furnace. The alloy was subjected to high temperature compression test by Gleeble-1500 thermal simulator. The phase structure of the alloy was analyzed by XRD. Results The alloy consists of white dendrite Nbss solid solution phase, gray continuous matrix Nb3Si phase and black massive Nb4Fe Si phase. When the sample is compressed at a relatively low temperature and a large deformation rate, brittle fracture occurs. In the range of 1200 ~ 1400 ℃, with the increase of deformation temperature and the decrease of deformation rate, the cracking tendency of specimen decreases and the stress peak decreases. Brittle Nb3Si phase becomes continuous island-like distribution, and the formation of eutectoid decomposition of small two-phase microstructure. Conclusion The high temperature compression process decreases the content of Nb3Si in the hard and brittle phases, increases the Nbss phase content in the tough phase, and decreases the high temperature strength of the alloy, which reduces the plastic working difficulty of the alloy to a certain extent.