Al含量微调对TiAl合金组织及压缩力学性能的影响

发布时间：2018-05-03 12:50

本文选题：TiAl合金 + 压缩力学性能　；参考：《稀有金属材料与工程》2017年03期

【摘要】：研究了Al含量对TiAl合金微观组织及压缩力学性能的影响,并分析其破坏机理。研究发现,Al含量对TiAl合金微观组织影响显著。通过真空自耗电弧冶炼方法制备的Ti-44.1Al(原子分数,%)合金的组织为全层片组织,层片团粗大,呈现柱状晶特征;而Ti-47.3Al合金的组织为双态组织,三维连通的网状γ相将粗大的铸造组织分割成细小的层片团。力学性能研究发现,与Ti-47.3Al合金相比,无论是在准静态还是动态压缩加载条件下,Ti-44.1Al合金都表现出较高的屈服强度,较低的抗压强度以及较差的塑性变形能力。破坏机理分析表明,准静态压缩加载条件下,在Ti-44.1Al合金中,微孔在γ/α_2层片团的α_2相中萌生并聚集形成裂纹;而在Ti-47.3Al合金中,微孔同时在γ/α2层片团中α_2相中以及三维连通的网状γ相中萌生,微孔聚集形成裂纹并扩展;动态压缩加载条件下,在Ti-44.1Al合金中,在γ/α_2层片团中存在大量的α_2相与γ相的相界,由于加载时间短,在相界处易引起位错塞积而导致应力集中,致使微裂纹在相界处迅速萌生并扩展;而在Ti-47.3Al合金中,微裂纹不仅在γ/α_2层片团中α_2相与γ相的相界处萌生,同时也会在三维连通的网状γ相中迅速萌生并扩展,直至材料破坏。
[Abstract]:The effect of Al content on the microstructure and compressive mechanical properties of TiAl alloy was studied and the failure mechanism was analyzed. It is found that Al content has a significant effect on the microstructure of TiAl alloy. The microstructure of Ti-44.1Al (atomic fraction) alloy prepared by vacuum consumable arc smelting method is a full-layer structure, the lamellar mass is thick, and the structure of Ti-47.3Al alloy is a two-state structure. The three-dimensional connected reticular 纬-phase divides the coarse cast structure into small lamellar clusters. The mechanical properties of Ti-44.1Al alloy show higher yield strength, lower compressive strength and lower plastic deformation ability than those of Ti-47.3Al alloy under quasi-static or dynamic compression loading. The failure mechanism analysis shows that, under quasi-static compression loading, the micropores in Ti-44.1Al alloy initiate and aggregate to form cracks in 伪 _ 2 phase of 纬 / 伪 _ 2 lamellae, while in Ti-47.3Al alloy, the crack is formed in the 伪 _ 2 phase of 纬 / 伪 _ 2 lamellae. The micropores germinate in 伪 _ 2 phase in 纬 / 伪 _ 2 lamellar cluster and in three-dimensional connected reticular 纬 phase at the same time, and micropore aggregates to form cracks and expand. Under dynamic compression loading conditions, there are a large number of 伪 _ 2 and 纬 phase boundaries in Ti-44.1Al alloy, and in 纬 / 伪 _ 2 lamellar cluster, there is a large number of phase boundaries between 伪 _ 2 phase and 纬 phase in 纬 / 伪 _ 2 lamellar cluster. Due to the short loading time, it is easy to cause dislocation accumulation at the phase boundary and lead to stress concentration, which leads to the rapid initiation and expansion of microcracks at the phase boundary, while in Ti-47.3Al alloy, the microcracks not only germinate at the phase boundaries of 伪 2 phase and 纬 phase in 纬 / 伪 2 layers. At the same time, it also rapidly germinates and expands in three-dimensional connected reticular 纬-phase until the material is destroyed.
【作者单位】：北京理工大学;北京航空材料研究院;国营121厂牡丹江北方合金工具有限公司;
【基金】：国家自然科学基金青年基金项目(51201013)
【分类号】：TG146.23

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