Article
Nanoscience & Nanotechnology
Fangzhou Qi, Xiaolong Zhang, Guohua Wu, Wencai Liu, Xie He, Wenjiang Ding
Summary: In this study, the effect of heat treatment on a novel sand-cast Mg-3Nd-2.6Gd-0.2Zn-0.5Zr alloy was evaluated, showing significant improvements in microstructure and mechanical properties after optimized solution treatment and peak-aged condition. The high cycle fatigue properties were found to be influenced by heat treatment conditions, with the peak-aged alloy showing the highest fatigue strength and a linear relationship with yield strength and ultimate tensile strength.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Engineering, Mechanical
Thomas Edward James Edwards, Fabio Di Gioacchino, William John Clegg
Summary: In a lamellar TiAl alloy, plastic deformation mainly occurs in soft-mode colonies through slip parallel to the lamellae and near lamellar interfaces under high cycle tensile fatigue conditions. At 25 degrees C, the maximum applied stress has a greater influence on the number of slip bands than the number of loading cycles.
INTERNATIONAL JOURNAL OF FATIGUE
(2021)
Article
Engineering, Mechanical
Guanze Sun, Rui Cao, Xin Zhou, Xiao Xia Jiang, Hongwei Wang
Summary: In this study, the high-cycle fatigue life of TNM-TiAl alloy under different stress ratios was investigated. The results showed that the fatigue life of the alloy is mainly affected by the mean stress and stress amplitude, decreasing with the increase of stress amplitude and the decrease of mean stress.
FATIGUE & FRACTURE OF ENGINEERING MATERIALS & STRUCTURES
(2022)
Article
Nanoscience & Nanotechnology
Alexander Schmiedel, Christina Burkhardt, Sebastian M. Rudolph, Anja Weidner, Horst Biermann
Summary: The fatigue lives of Ti-48Al-2Cr-2Nb alloy were investigated in both additive manufacturing and conventional casting process. The additive manufactured material showed superior fatigue strength due to its smaller grain size.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Article
Materials Science, Multidisciplinary
Jie Ding, Shuntian Huang, Zhili Dong, Junpin Lin, Yang Ren, Xiaodong Wu, Hui Chang
Summary: The study found that different phases in high-Nb-containing TiAl alloy experience different lattice strains during low-cycle fatigue, with larger compressive lattice strains formed during cooling impacting the lattice condition of the alloy. The performed synchrotron experiments also revealed the phase transformations and micromechanisms of these alloys during low-cycle fatigue.
ADVANCED ENGINEERING MATERIALS
(2021)
Article
Materials Science, Multidisciplinary
Peirong Ren, Weiqing Huang, Zhengxing Zuo, Dongwei Li, Chengzhang Zhao, Kangjie Yan
Summary: This study investigates the high cycle fatigue behavior of Al-Si alloy extracted from a cylinder head through experiments and finite element simulations. The microstructure characteristics of the cylinder head exhibit high spatial heterogeneity due to the complexity of the structure and differences in cooling rates and local melt flow. The scatter of the alloy's fatigue life is high and significantly affected by the microstructure, particularly crack nucleation pores.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2022)
Article
Nanoscience & Nanotechnology
Gang Liu, Jordi Salvat Canto, Soran Birosca, Shuai Wang, Yonghua Zhao
Summary: IN713C nickel-based superalloy is widely used in automobile industry and experiences high cycle fatigue (HCF) or very-HCF failure. Casting process-induced grain structure/ size variations significantly influence its fatigue life. This study investigates HCF testing of IN713C cast bars with different grain structures and sizes under similar stress level (-300 MPa) at 650 degrees C. The fatigue life, ranging from -87,000 to 10 x 106 cycles, is primarily determined by porosity and faceting grain size. Smaller pore size delays faceting and increases fatigue life, while smaller facet (grain) size leads to lower crack propagation rate and longer loading cycles, ultimately contributing to higher fatigue life. This research reveals the beneficial effect of smaller grain size on fatigue property, particularly in reducing initial crack propagation rate, which has been rarely reported before.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Article
Materials Science, Multidisciplinary
Jung Eun Kim, Ye Jin Kim, Jun Ho Bae, Bong Sun You, Sung Hyuk Park
Summary: This study investigates the microstructural characteristics, tensile properties, and high-cycle fatigue properties of a die-cast Mg-6Al-0.1Mn-0.1Zn-0.3Ca-0.2Y (SEN6) alloy with high corrosion and ignition resistances. The average grain size of the SEN6 alloy is smaller at the surface region compared to the center region due to higher cooling rate. The presence of Ca and Y results in the formation of various particles. The alloy exhibits a tensile yield strength, ultimate tensile strength, elongation, and fatigue limit. Different types of pores act as crack initiation sites during tension and fatigue. The relationship between fatigue limit and ultimate tensile strength is observed in the SEN6 alloy.
METALS AND MATERIALS INTERNATIONAL
(2023)
Article
Engineering, Mechanical
Jiamei Zhang, Jianghua Li, Shengchuan Wu, Wenjie Zhang, Jingyu Sun, Guian Qian
Summary: This study investigated the effects of defects and building directions on the high-cycle fatigue and very-high-cycle fatigue performance of additive manufactured AlSi10Mg using crystal plasticity finite element analysis. The results showed that specimens with defects had significantly lower fatigue life compared to those without defects, and samples built at 0 degrees exhibited better fatigue performance than those built at 90 degrees. This work is valuable for determining fatigue lifetime and enhancing the fatigue behavior of AlSi10Mg.
INTERNATIONAL JOURNAL OF FATIGUE
(2022)
Article
Engineering, Mechanical
Ahmad Nourian-Avval, Ali Fatemi
Summary: This article investigates the fatigue performance of A356-T6 aluminum alloy under different loading conditions, revealing that fatigue cracks initiated from defects, mainly porosity, and grew on the plane of maximum principal stress. Experimental fatigue life data were predicted using small crack growth models and maximum defect size estimated by extreme value statistics, showing very good agreements with the actual fatigue lives under different loading conditions.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2021)
Article
Materials Science, Multidisciplinary
Xiaoping Zhu, Chunlei Zhu, Baosen Lin, Zidong Wang
Summary: The effect of the cast process procedure and pouring systems on several typical metallurgical defects for TiAl case casting was studied. Gravity casting showed better melt-filling stability and synchronization compared to centrifugal casting. By designing a suitable inner-gate structure and increasing the bottom cross runners, the misrun defects in the thin-walled outer ring and the negative effect of overheated zone in the thick-walled flange could be effectively resolved. The crack induced by stress concentration in the transition zone poses significant challenges for TiAl case casting and can be resolved through structural design and process optimization.
Article
Mechanics
Han Wu, Chengqi Sun, Wei Xu, Xin Chen, Xiaolei Wu
Summary: In this paper, a continuous runout method (CRM) is proposed to evaluate the fatigue strength in high cycle and very high cycle fatigue regimes based on the probability and statistics theory. The CRM features the simultaneous testing of multiple samples, which reduces the testing period to 1/5-1/3 of that by the common up-and-down method for 16 samples. Experimental data for G20Mn5QT steel, 40 Cr steel, and Ti-6Al-4V alloy validate the CRM's predicted lower limits of fatigue strength, which are slightly more conservative than those obtained by the up-and-down method.
ENGINEERING FRACTURE MECHANICS
(2023)
Article
Engineering, Mechanical
Litton Bhandari, Vidit Gaur
Summary: This study investigates the cyclic behavior and cold dwell sensitivity of additively manufactured Ti6Al4V alloy. Low cycle fatigue tests were conducted on specimens exposed to a dwell period, revealing a significant reduction in fatigue lives at lower strain amplitudes but similar lives at higher ones. Fractographic analysis identified multiple crack initiation regions, attributed to process-induced defects or facet formation in α laths. The study discusses the failure mechanism based on stress redistribution and relaxation.
ENGINEERING FAILURE ANALYSIS
(2023)
Article
Engineering, Mechanical
Pei-rong Ren, Wei Song, Gu Zhong, Wei-qing Huang, Zheng-xing Zuo, Cheng-zhang Zhao, Kang-jie Yan
Summary: Several cast Al-Si alloy cylinder heads fractured prematurely at the same position during high-cycle fatigue (HCF) bench test, with the root cause identified as large defects near the surface and poor microstructure characteristics of the alloy, rather than external load. The yield strength, ultimate tensile strength, and elongation at the failure location showed significant reductions compared to non-failure locations, resulting in lower HCF strength of the cylinder head.
ENGINEERING FAILURE ANALYSIS
(2021)
Article
Materials Science, Multidisciplinary
Chuanli Yu, Zhiyong Huang, Zian Zhang, Jian Wang, Jiebin Shen, Zhiping Xu
Summary: Additive manufacturing has great potential in manufacturing complex and precise parts, but defects generated during the process limit its applications. This study used ultrasonic fatigue testing to evaluate the effects of sandblasting and hot isostatic pressing on the very high cycle fatigue (VHCF) performance of IN718 fabricated by selective laser melting. Characterization of defects, including size and location, was done using X-ray computed tomography and a 3D-optical profiler. Sandblasting improved the surface state and shifted crack initiation sites from the surface to the interior. With the elimination of defects and the introduction of compressive residual stress, the fatigue resistance was significantly improved.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2022)
