Masahiro Goto , Takaei Yamamoto , Sangshik Kim , Eun-Ae Choi , Seung Zeon Han
{"title":"Effect of grain boundary phase formed by Mn addition on initiation and propagation of fatigue cracks in homogenized Cu-6Ni-1.3Si alloy","authors":"Masahiro Goto , Takaei Yamamoto , Sangshik Kim , Eun-Ae Choi , Seung Zeon Han","doi":"10.1016/j.ijfatigue.2024.108731","DOIUrl":null,"url":null,"abstract":"<div><div>High-strength cast Cu alloys often contain substantial quantities of alloying elements that promote the nucleation of heterogeneous particles, particularly at grain boundaries (GBs). In the Cu-6Ni-1.3Si alloy, intermetallic compounds such as Ni<sub>2</sub>Si form within the matrix and along the GBs following homogenization. Ni<sub>2</sub>Si particles within the matrix are homogeneously nucleated with diameters of a few tens of nanometers, which enhances matrix strength. However, heterogeneously nucleated Ni<sub>2</sub>Si particles at GBs, which can be several micrometers in size, negatively impact overall strength. To improve the strength of Cu-6Ni-1.3Si alloy, 2.1 wt% Mn was added. This Mn addition led to the formation of plate- or film-shaped intermetallic compounds, specifically Ni<sub>16</sub>Si<sub>7</sub>Mn<sub>6</sub> (G-phase), at GBs after homogenization. Despite the Mn addition, Ni<sub>2</sub>Si precipitates with diameters of a few tens of nanometers still formed within the grains, but these were more densely distributed in the Mn-added alloy compared to the Mn-free alloy. Fatigue tests conducted on round bar specimens of both alloys showed that Mn addition enhanced fatigue strength. This enhancement is attributed to the suppression of both crack initiation and propagation along the GBs and within the matrix.</div></div>","PeriodicalId":14112,"journal":{"name":"International Journal of Fatigue","volume":"192 ","pages":"Article 108731"},"PeriodicalIF":5.7000,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"International Journal of Fatigue","FirstCategoryId":"88","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0142112324005905","RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ENGINEERING, MECHANICAL","Score":null,"Total":0}
引用次数: 0
Abstract
High-strength cast Cu alloys often contain substantial quantities of alloying elements that promote the nucleation of heterogeneous particles, particularly at grain boundaries (GBs). In the Cu-6Ni-1.3Si alloy, intermetallic compounds such as Ni2Si form within the matrix and along the GBs following homogenization. Ni2Si particles within the matrix are homogeneously nucleated with diameters of a few tens of nanometers, which enhances matrix strength. However, heterogeneously nucleated Ni2Si particles at GBs, which can be several micrometers in size, negatively impact overall strength. To improve the strength of Cu-6Ni-1.3Si alloy, 2.1 wt% Mn was added. This Mn addition led to the formation of plate- or film-shaped intermetallic compounds, specifically Ni16Si7Mn6 (G-phase), at GBs after homogenization. Despite the Mn addition, Ni2Si precipitates with diameters of a few tens of nanometers still formed within the grains, but these were more densely distributed in the Mn-added alloy compared to the Mn-free alloy. Fatigue tests conducted on round bar specimens of both alloys showed that Mn addition enhanced fatigue strength. This enhancement is attributed to the suppression of both crack initiation and propagation along the GBs and within the matrix.
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.