Fracture toughness of titanium alloys fabricated by high-power laser-directed energy deposition: Fractal analysis and prediction model

被引：0

作者：

Ren, Yongming ^{[1
]}

Cao, Yuanshuai ^{[1
]}

Liu, Yongqin ^{[1
]}

Jie, Ziqi ^{[1
]}

Jian, Zengyun ^{[1
]}

Zhu, Man ^{[1
]}

Huang, Shixing ^{[1
]}

Wang, Meng ^{[2
]}

Zhou, Yinghui ^{[1
]}

Lin, Xin ^{[2
]}

Huang, Weidong ^{[2
]}

机构：

[1] School of Materials and Chemical Engineering, Xi'an Technological University, Xi'an,710021, China

[2] State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi'an,710072, China

来源：

Journal of Materials Science and Technology | 2025年 / 228卷

基金：

中国国家自然科学基金;

关键词：

After-heat treatment - Enameling - Epitaxial growth - Fractal dimension - Fracture mechanics - Fracture testing - Fracture toughness - High energy electron diffraction - Laser materials processing - Prediction models;

D O I：

10.1016/j.jmst.2024.12.027

中图分类号：

学科分类号：

摘要：

Laser additive-manufactured (AM) metallic components typically have superior uniaxial tensile strength to their conventional processing counterparts. However, the strength and toughness trade-off for most AM-fabricated metallic parts remains unsolved. Generally, the heat treatment processes can enhance the elongation and toughness of as-deposited AM samples. In this work, the fracture toughness of high-power (7600 W) laser directed energy deposition Ti–6Al–4V (Ti64) + heat treatment (short as Ti64 DED-HT) samples, were studied using fracture property tests. Combining electron backscatter diffraction (EBSD), confocal laser scanning microscope, and fractal geometry theory, we investigated their fracture mechanism and proposed a new prediction model between plane-strain fracture toughness (KIc) and conventional tensile properties. The results show that the plane-strain fracture toughness value in four states (two scanning speeds and two directions) is 81.3 ± 0.7 MPa m1/2, higher than that of the wrought counterparts (∼65 MPa m1/2). This high plane-strain fracture toughness results from the combination of relatively fine columnar β grains and coarse α laths of the deposited parts after a specific heat-treated process. Combined with a confocal laser scanning microscope and fractal geometry analysis theory, we found that the rough surface profile leads to high fractal dimension values. In addition, we proposed a modified analytical prediction model, which can effectively predict the plane-strain fracture toughness value of AM Ti64 titanium alloys. These findings provide a guideline for obtaining a high strength–toughness and reliably predicting its KIc value in AM titanium alloys. © 2025

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页码：54 / 74