Chapter 19
Fatigue Crack Growth of TC4 Titanium
Alloy Using Acoustic Emission Technique
Wenjun Zhang, Gongtian Shen, and Yongna Shen
Abstract In this paper, the crack propagation process of TC4 titanium alloy was
studied by using acoustic emission detection technology, and the trend analysis
method and the correlation analysis method of the characteristic parameters of the
acoustic emission are used to process and analyze the acoustic emission signal during
the fatigue crack growth process. The results show that the acoustic emission counting
parameters can well characterize the three stages of crack growth of TC4 titanium
alloy: response to the initiation zone, steady-state extension zone and unstable fracture zone of fatigue crack. It provides a basis for the further use of acoustic emission
technology for online monitoring and early warning analysis of TC4 titanium alloy.
19.1 Introductions
Fatigue damage is one of the main failure modes of aero-engine components. The
basic process can be divided into three stages: crack initiation, stable crack propagation and unstable crack propagation [1]. First, the lattice structure of the material will
generate stress concentration due to dislocation plugging, and then form a source of
crack fatigue [2, 3]. This is the crack initiation stage; next, because the TC4 titanium alloy has a certain plasticity, the crack continues to expand after the crack is
formed in a long time process. In this process, the local stress of the material is periodically released, and accompanied by the generation of acoustic emission signals.
This process is the stage of stable crack growth. And the third stage is the unstable
fracture stage of fatigue crack propagation. At the same time, this process occurs
almost instantaneously. The energy released during this period is very large, which
will produce a high-intensity AE signal. Due to the sudden type [4], it often causes
catastrophic accidents. Therefore, in order to prevent early fatigue failure of materials, the detection and evaluation of the early fatigue state of materials is intuitively
important.
W. Zhang · G. Shen (B) · Y. Shen
China Special Equipment Inspection and Research Institute, Beijing 100029, China
e-mail: zwj787404079@163.com
© The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2021
G. Shen et al. (eds.), Advances in Acoustic Emission Technology, Springer Proceedings
in Physics 259, https://doi.org/10.1007/978-981-15-9837-1_19
213
Fatigue Crack Growth of TC4 Titanium
Alloy Using Acoustic Emission Technique
Wenjun Zhang, Gongtian Shen, and Yongna Shen
Abstract In this paper, the crack propagation process of TC4 titanium alloy was
studied by using acoustic emission detection technology, and the trend analysis
method and the correlation analysis method of the characteristic parameters of the
acoustic emission are used to process and analyze the acoustic emission signal during
the fatigue crack growth process. The results show that the acoustic emission counting
parameters can well characterize the three stages of crack growth of TC4 titanium
alloy: response to the initiation zone, steady-state extension zone and unstable fracture zone of fatigue crack. It provides a basis for the further use of acoustic emission
technology for online monitoring and early warning analysis of TC4 titanium alloy.
19.1 Introductions
Fatigue damage is one of the main failure modes of aero-engine components. The
basic process can be divided into three stages: crack initiation, stable crack propagation and unstable crack propagation [1]. First, the lattice structure of the material will
generate stress concentration due to dislocation plugging, and then form a source of
crack fatigue [2, 3]. This is the crack initiation stage; next, because the TC4 titanium alloy has a certain plasticity, the crack continues to expand after the crack is
formed in a long time process. In this process, the local stress of the material is periodically released, and accompanied by the generation of acoustic emission signals.
This process is the stage of stable crack growth. And the third stage is the unstable
fracture stage of fatigue crack propagation. At the same time, this process occurs
almost instantaneously. The energy released during this period is very large, which
will produce a high-intensity AE signal. Due to the sudden type [4], it often causes
catastrophic accidents. Therefore, in order to prevent early fatigue failure of materials, the detection and evaluation of the early fatigue state of materials is intuitively
important.
W. Zhang · G. Shen (B) · Y. Shen
China Special Equipment Inspection and Research Institute, Beijing 100029, China
e-mail: zwj787404079@163.com
© The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2021
G. Shen et al. (eds.), Advances in Acoustic Emission Technology, Springer Proceedings
in Physics 259, https://doi.org/10.1007/978-981-15-9837-1_19
213