Crack initiation and propagation characteristics of a dual‐phase Mg–Li alloy under high‐cycle and very‐high‐cycle fatigue regimes

2021 ◽  
Author(s):  
Xiangyu Wang ◽  
Chao He ◽  
Xue Li ◽  
Yongjie Liu ◽  
Qingyuan Wang ◽  
...  
Keyword(s):  
Crack Initiation ◽  
High Cycle Fatigue ◽  
Dual Phase ◽  
Cycle Fatigue ◽  
Propagation Characteristics ◽  
Crack Initiation And Propagation ◽  
Very High Cycle Fatigue ◽  
Initiation And Propagation ◽  
Very High

Very-high-cycle fatigue crack initiation and propagation behaviours of magnesium alloy ZK60

2017 ◽  
Vol 34 (6) ◽  
pp. 639-647 ◽  
Author(s):  
Chao He ◽  
Yongjie Liu ◽  
Jiukai Li ◽  
Kun Yang ◽  
Qingyuan Wang ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Magnesium Alloy ◽  
Crack Initiation ◽  
High Cycle Fatigue ◽  
Fatigue Crack Initiation ◽  
Cycle Fatigue ◽  
Crack Initiation And Propagation ◽  
Very High Cycle Fatigue ◽  
Initiation And Propagation ◽  
Very High

Review on Surface Failure Mode of Metallic Materials in Very High Cycle Fatigue Regime

2013 ◽  
Vol 652-654 ◽  
pp. 1295-1300
Author(s):  
Dong Ming Wang ◽  
Wei Li ◽  
Ping Wang ◽  
Wei Xian Chu
Keyword(s):  
Crack Initiation ◽  
Surface Crack ◽  
High Cycle Fatigue ◽  
Metallic Materials ◽  
Crack Initiation And Propagation ◽  
Surface Failure ◽  
Very High Cycle Fatigue ◽  
Initiation And Propagation ◽  
Very High ◽  
Surface Crack Initiation

With higher cleanness upgraded steadily, surface failure of metallic materials in very high cycle fatigue (VHCF) regime beyond 107 cycles has been reported one after another. The occurrence of surface crack initiation to failure in VHCF regime is closely related to the following factors: (i) surface finishing condition of specimen, i.e. whether some grinding scratches, grooves and cavities with a relatively larger size than the subsurface defect exist at the surface of specimen; (ii) type, size, location, distribution and density of metallurgical defects such as inclusion contained in the subsurface of material; (iii) degree of persistent slip band (PSB) deformation induced by surface roughening of specimen, mainly corresponding to the some ductile single-phase metallic materials. Furthermore, the effect of environment such as humidity also accelerates surface crack initiation and propagation in VHCF regime. In the present paper, the authors briefly reviewed surface failure modes of metallic materials in VHCF regime beyond 107 cycles, and analyzed the surface crack initiation and propagation mechanisms from the viewpoints of the fracture mechanics and statistics.

scholarly journals Crack initiation and propagation mechanisms of an extruded dual-phase Magnesium-Lithium alloy in very high cycle fatigue regime

2021 ◽  
Author(s):  
Xiangyu WANG ◽  
Chao HE ◽  
Xue LI ◽  
YongJie Liu ◽  
Qingyuan Wang ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Crack Initiation ◽  
High Cycle Fatigue ◽  
Fatigue Crack Initiation ◽  
Extrusion Direction ◽  
Cyclic Plasticity ◽  
Dual Phase ◽  
Cycle Fatigue ◽  
Very High Cycle Fatigue ◽  
Very High

Ultra-light Mg-Li alloy is a promising alloy in aerospace since it is known to the lightest structural alloy at present, but its fatigue behaviors remain to be explored. This work focuses on very-high cycle fatigue (VHCF) strength and small crack initiation behaviors of an extruded dual-phase Mg-Li alloy (LZ91). The fatigue strength of the LZ91 alloy at 109 cycles is about 78 MPa, and the fatigue ratio is approximately 0.46. Microstructure characterization demonstrates that fatigue crack tends to initiate from the β-Li phase-enriched region. The α-Mg phase, presenting <10−10 >  fiber texture with the basal plane, deforms hardly along the extrusion direction and acts as an enhanced phase compared with the β-Li phase. The deformation discrepancy localizes cyclic plasticity at the Li phase and finally leads to the fatigue crack initiation.

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