Ti-22Al-15Nb合金的力学性能及破坏机理研究
发布时间：2018-10-13 15:10
【摘要】：研究了名义成分为Ti-22Al-15Nb的Ti-Al系合金的微观组织和力学性能,以及在准静态和动态加载条件下的变形行为,并对其破坏机理进行了分析。微观组织研究表明,Ti-22Al-15Nb合金铸态组织为等轴晶,晶内主要由α2-Ti3Al相和B2-Ti2AlNb相组成,具有随机取向的片状α2相均匀分布在B2基相上。力学性能研究表明,合金在动态加载条件下表现出较优异的性能,其屈服强度为1 100 MPa,抗压强度为1 750 MPa,且在动态加载下具有更好的塑性。破坏机理分析表明,在准静态加载条件下,合金试样发生剪切破坏,微裂纹首先在α2相及α2相与B2相的相界处萌生,在最大剪应力方向上扩展形成主裂纹,最终导致合金试样破坏;在动态加载条件下,合金的破坏方式为绝热剪切破坏,即在与加载轴呈45°角的方向上形成绝热剪切带,随着应变的增大,裂纹在剪切带中萌生并扩展,最终破坏合金试样。
[Abstract]:The microstructure and mechanical properties of Ti-Al alloy with nominal composition of Ti-22Al-15Nb and its deformation behavior under quasi-static and dynamic loading were studied. The failure mechanism of the alloy was analyzed. Microstructure study shows that the as-cast structure of Ti-22Al-15Nb alloy is equiaxed, which is mainly composed of 伪 2-Ti3Al phase and B2-Ti2AlNb phase. The lamellar 伪 2 phase with random orientation distributes uniformly on B2 base phase. The mechanical properties show that the alloy exhibits excellent properties under dynamic loading, its yield strength is 1 100 MPa, compressive strength is 1 750 MPa, and it has better plasticity under dynamic loading. The failure mechanism analysis shows that under the quasi-static loading condition, the shear failure of the alloy specimen occurs, and the microcracks first germinate at the phase boundaries of 伪 2 phase and 伪 2 phase and B2 phase, and form the main crack in the direction of the maximum shear stress. Under dynamic loading condition, the failure mode of the alloy is adiabatic shear failure, that is, the adiabatic shear band is formed in the direction of 45 掳angle to the loading axis. With the increase of strain, the crack begins and expands in the shear band. The final failure of the alloy specimen.
【作者单位】： 北京理工大学材料学院;北京航空材料研究院;北京理工大学爆炸科学与技术重点实验室;
【基金】：国家自然科学基金(51571033)
【分类号】：TG146.23
本文编号：2269066
[Abstract]:The microstructure and mechanical properties of Ti-Al alloy with nominal composition of Ti-22Al-15Nb and its deformation behavior under quasi-static and dynamic loading were studied. The failure mechanism of the alloy was analyzed. Microstructure study shows that the as-cast structure of Ti-22Al-15Nb alloy is equiaxed, which is mainly composed of 伪 2-Ti3Al phase and B2-Ti2AlNb phase. The lamellar 伪 2 phase with random orientation distributes uniformly on B2 base phase. The mechanical properties show that the alloy exhibits excellent properties under dynamic loading, its yield strength is 1 100 MPa, compressive strength is 1 750 MPa, and it has better plasticity under dynamic loading. The failure mechanism analysis shows that under the quasi-static loading condition, the shear failure of the alloy specimen occurs, and the microcracks first germinate at the phase boundaries of 伪 2 phase and 伪 2 phase and B2 phase, and form the main crack in the direction of the maximum shear stress. Under dynamic loading condition, the failure mode of the alloy is adiabatic shear failure, that is, the adiabatic shear band is formed in the direction of 45 掳angle to the loading axis. With the increase of strain, the crack begins and expands in the shear band. The final failure of the alloy specimen.
【作者单位】： 北京理工大学材料学院;北京航空材料研究院;北京理工大学爆炸科学与技术重点实验室;
【基金】：国家自然科学基金(51571033)
【分类号】：TG146.23
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