Microstructure-sensitive fatigue crack growth in lath martensite of low carbon steel

Ueki, Shohei; Mine, Yoji; Takashima, Kazuki

doi:10.1016/j.msea.2019.138830

Cited by 27 publications

(15 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…On the one hand, an impingement of slip bands on the PAGBs was found causing intergranular crack formation, as also described in Batista et al and Krupp et al [11,14] On the other hand, some intergranular crack initiation sites exhibited just one slip step at the PAGB which coincides with Motoyashiki et al [15] However, it should be noted that Motoyashiki et al observed a transgranular early short crack propagation in the depth direction after intergranularly crack initiation. Intergranularly crack initiation at block boundaries as cited in the studies by Batista et al and Ueki et al [11,16] or transgranularly crack initiation as in the case of previous studies [7,9,13] was not observed. Morrison and Moosbrugger [20] studied the fatigue behavior of fine grain and coarse grain nickel-270 and in the case of coarse grain nickel, the crack initiation occurred almost exclusively at grain boundaries where slip bands impinged.…”

Section: Discussionmentioning

confidence: 62%

“…[11][12][13] It seems that those slip bands do not cross microstructural interfaces with a high-angle boundary like packet boundaries or prior austenite grain boundaries (PAGBs). [10,13,14] Hence, the crack initiation and early short crack propagation in martensitic steels seem to occur mainly intergranularly at PAGBs [11,12,14,15] or block boundaries, [11,16] although in some studies, transgranular crack initiation and early short crack propagation were also observed. [9,13] In many studies, the preferential alignment of carbides along microstructural interfaces is cited as a possible reason for intergranular crack initiation and early short crack propagation.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Characterizing the Fatigue Damage in a Martensitic Spring Steel

Wildeis

Christ

Brandt

et al. 2021

steel research int.

View full text Add to dashboard Cite

Many technical components are subjected to uniaxial cyclic loading in the high cycle fatigue regime. The resulting fatigue damage evolution is commonly subdivided into four stages, i.e., crack initiation, short crack propagation, long crack propagation, and eventually failure. Especially, the stages of crack initiation and short crack propagation can account for up to 90% of the fatigue life in the high cycle fatigue regime, leading to a particular interest in investigating these stages of fatigue damage evolution. [1] Furthermore, it is extremely important to understand the mechanisms of crack initiation and short crack propagation for lifetime predictions of structures which are not fail safe, as their failure can cause a catastrophic damage.Many studies have shown, that crack initiation often occurs at slip bands (see for example, the studies by Christ, McEvily, Efthymiadis et al., and Hong et al. [1][2][3][4] ) and that short crack propagation is strongly influenced by the local microstructure, leading to an oscillating crack propagation rate (see for example, the studies by Christ, McEvily, Miller, and Yang et al. [1,2,5,6] ). However, until now, just a few studies have investigated the fatigue damage evolution in a martensitic steel and the corresponding impact of the complex martensitic microstructure on the crack initiation and the short crack propagation. The crack initiation in martensitic steels seems to occur often at slip bands, [7][8][9][10][11] which mainly arise at microstructural interfaces and are oriented parallel to martensitic laths. [11][12][13] It seems that those slip bands do not cross microstructural interfaces with a high-angle boundary like packet boundaries or prior austenite grain boundaries (PAGBs). [10,13,14] Hence, the crack initiation and early short crack propagation in martensitic steels seem to occur mainly intergranularly at PAGBs [11,12,14,15] or block boundaries, [11,16] although in some studies, transgranular crack initiation and early short crack propagation were also observed. [9,13] In many studies, the preferential alignment of carbides along microstructural interfaces is cited as a possible reason for intergranular crack initiation and early short crack propagation. [7,14,17,18] In addition, intergranular crack initiation can be explained by the impingement of slip bands on grain boundaries [14,19,20] or the anisotropic elastic and plastic properties of the grains. [11,12,15,[21][22][23] The number of slip bands formed and cracks initiated rises with increasing number of cycles and with increasing stress amplitude. [4,8,9,13,24] The subsequent short crack propagation seems to be strongly influenced by the local microstructure, whereby a short crack propagation parallel to the martensitic laths is often observed. [8,24,25] PAGBs [6,8,14,24,26] and block boundaries [6,7,26] seem to act as obstacles for short crack propagation, leading to an oscillating short crack propagation rate. An often referred explanation for the barrier effect of microstructural interfaces is the...

show abstract

Section: Discussionmentioning

confidence: 62%

mentioning

confidence: 99%

Characterizing the Fatigue Damage in a Martensitic Spring Steel

Wildeis

Christ

Brandt

et al. 2021

steel research int.

View full text Add to dashboard Cite

show abstract

“…The laths were interphased at a small angle between the grain boundaries, and the phase difference is small, so it is more difficult to slip between the martensite laths. Moreover, it is also difficult for cracks to pass through the lath martensite bundles from initiation to growth, which leads to a high fatigue limit of the material [ 25 ].…”

Section: Discussionmentioning

confidence: 99%

Low-Cycle Fatigue Behavior of the Novel Steel and 30SiMn2MoV Steel at 700 °C

Zhao

Zhang

et al. 2020

Materials

View full text Add to dashboard Cite

As a newly developed gun barrel steel, the novel steel has shown excellent high-temperature strength, high resistance to wear and erosion, contributing to the superior ballistic life of gun barrels. As ballistic life increases, the fatigue life becomes essential for the safety and reliability of gun barrels. This paper presents a comparison of the low cycle fatigue (LCF) behaviors between a novel steel and 30SiMn2MoV steel at 700 °C. A strain-controlled fatigue test was carried out on the novel steel and 30SiMn2MoV steel in the strain range from 0.2 to 0.6%. The cyclic stress response behaviors of the novel steel and 30SiMn2MoV steel show cyclic softening behavior. In addition, the shape of the hysteresis rings of the novel steel and 30SiMn2MoV steel exhibit no-Masing model behavior. Energy–life relationships results show that the novel steel has higher fatigue resistance than the 30SiMn2MoV steel at 700 °C. The results of fatigue fracture analysis show that the failure mode of the 30SiMn2MoV steel is a mixed mode of intergranular fracture and transgranular fracture, while the failure mode of the novel steel is intergranular fracture. The cyclic softening of the two materials can be attributed to the lath structure with a high density of dislocations gradually transforms into low energy subcrystalline and cellular structures at 700 °C. The novel steel has a better fatigue life than the 30SiMn2MoV steel at 700 °C and different strain amplitudes, which is mainly related to the carbides and lath martensite in the materials.

show abstract

“…The microstructure of the base metal is tempered sorbite, while that of the laser zone and arc zone are lath martensite due to the fast cooling rate of the hybrid laserarc welding process. Compared with the tempered sorbite, the lath martensite containing high density dislocation is plastic deformed in the front of the fatigue crack tip [33,34]. Therefore, the stress concentration in the front of the fatigue crack propagation is reduced to a certain extent due to the large plastic deformation in the front of the fatigue crack propagation.…”

Section: Effect Of Microstructure On the Fatigue Crack Propagationmentioning

confidence: 99%