Research on the microscopic characteristics of low-cycle-fatigue and creep coupling in cast aluminum alloys for cylinder heads

IF 5.7 2区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Fatigue Pub Date : 2025-03-22 DOI:10.1016/j.ijfatigue.2025.108952

Jie Yan, Zicong Cao, Weizheng Zhang, Shuang Jin, Zhenyao Guo, Yanpeng Yuan, Haoyu Ma

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引用次数: 0

Abstract

As one of the most structurally complex components in diesel engines, the cylinder head is subjected to increasing thermal loads. This paper investigates the microscopic characteristics of fracture morphology in cast aluminum alloy materials for cylinder heads under high-temperature low-cycle-fatigue-creep (LCFC) coupling conditions. The study explores the effect of creep on the microscopic evolution of the material’s microstructure, clarifies the fracture failure modes, and identifies the underlying causes. The results show that at 250 °C, the fracture surfaces in low-cycle-fatigue (LCF) tests mainly exhibit brittle fracture characteristics. As the temperature increases, the fracture gradually transitions from brittle to ductile. Due to the influence of creep, the fracture surfaces in LCFC tests already show ductile fracture characteristics at 250 °C. Microscopic observations reveal that the reasons for the more pronounced cyclic softening phenomenon in LCFC conditions are attributed to creep’s effects on dislocation annihilation, dislocation rearrangement, and the coarsening and dissolution of precipitates. Two fracture modes, defect-induced fracture and Si-phase fracture, are proposed. Observations indicate that high-temperature creep can cause the eutectic Si structures within the material to fracture more easily, thereby altering the fracture mode.

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来源期刊

International Journal of Fatigue 工程技术-材料科学：综合

CiteScore

10.70

自引率

21.70%

发文量

619

审稿时长

58 days

期刊介绍： Typical subjects discussed in International Journal of Fatigue address: Novel fatigue testing and characterization methods (new kinds of fatigue tests, critical evaluation of existing methods, in situ measurement of fatigue degradation, non-contact field measurements) Multiaxial fatigue and complex loading effects of materials and structures, exploring state-of-the-art concepts in degradation under cyclic loading Fatigue in the very high cycle regime, including failure mode transitions from surface to subsurface, effects of surface treatment, processing, and loading conditions Modeling (including degradation processes and related driving forces, multiscale/multi-resolution methods, computational hierarchical and concurrent methods for coupled component and material responses, novel methods for notch root analysis, fracture mechanics, damage mechanics, crack growth kinetics, life prediction and durability, and prediction of stochastic fatigue behavior reflecting microstructure and service conditions) Models for early stages of fatigue crack formation and growth that explicitly consider microstructure and relevant materials science aspects Understanding the influence or manufacturing and processing route on fatigue degradation, and embedding this understanding in more predictive schemes for mitigation and design against fatigue Prognosis and damage state awareness (including sensors, monitoring, methodology, interactive control, accelerated methods, data interpretation) Applications of technologies associated with fatigue and their implications for structural integrity and reliability. This includes issues related to design, operation and maintenance, i.e., life cycle engineering Smart materials and structures that can sense and mitigate fatigue degradation Fatigue of devices and structures at small scales, including effects of process route and surfaces/interfaces.