Issue |
JNWPU
Volume 38, Number 5, October 2020
|
|
---|---|---|
Page(s) | 1025 - 1029 | |
DOI | https://doi.org/10.1051/jnwpu/20203851025 | |
Published online | 08 December 2020 |
In-Situ SEM Study on Deformation and Failure Mechanism of TC4 Titanium Alloy by Laser Additive Manufacturing
SEM原位加载研究激光增材制造TC4合金变形破坏机制
School of Aeronautics, Northwestern Polytechnical University, Xi'an 710072, China
Received:
20
January
2020
The in-situ tensile test of the field emission scanning electron microscope was used to study the deformation mechanism of the TC4 titanium alloy manufactured by laser additive manufacturing along the L direction (grain growth direction) and T direction (perpendicular to the grain growth direction). The test results show that during the tensile process, as deposited specimen mainly cracks along the interfaces of α and β which is 45 ° to the tensile direction. With the increase of load, the cracking increases. The surface of the sample fluctuates until breaks. There is no obvious change in the prior β grain boundary in L direction. The microcracks along grain boundaries were observed in T direction, which is consistent with the result that the plasticity in the T direction is less than that in L direction. After heat treatment, due to the increase of α lath width compared with the as-deposition, slip bands were observed in α phase. However, a large number of slip bands appear on the equiaxed α phase of the forged specimen.
摘要
利用扫描电镜的原位拉伸台研究了激光增材制造TC4钛合金沿晶粒生长方向(L)和垂直于晶粒生长方向(T)拉伸过程中的变形机理。结果表明沉积态拉伸过程中显微组织主要沿与拉伸方向呈约45°的α,β两相界面开裂;随着流动应力的增加,微裂纹数量增多,试样表面在载荷作用下出现起伏错动,直至破坏。L方向原始β晶界上没有明显的变化,T方向观察到沿晶界开裂的微裂纹,这与T方向的塑性比L方向差的结果相一致。热处理后由于α板条变宽,α相内出现滑移带,锻造态则是在等轴α相上出现了大量的滑移带。
Key words: additive manufacturing / titanium alloy / in-situ tension test / deformation mechanism
关键字 : 增材制造 / 钛合金 / 原位拉伸 / 变形机理
© 2020 Journal of Northwestern Polytechnical University. All rights reserved.
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