Fatigue Modeling Containing Hardening Particles and Grain Orientation for Aluminum Alloy FSW Joints

Abstract

The macro-mesoscopic joint fatigue model containing hardening particles and crystal characteristics is established to study the effect of the hardening particles and the grain orientation on fatigue properties of an aluminum alloy friction stir welding (FSW) joint. The macroscopic model is composed of the weld nugget zone, thermo-mechanically affected zone, heat-affected zone, and base material, according to the metallurgical morphology and hardness distribution of the joint. Cyclic stress and strain data are used to determine the material properties. The fatigue parameters used in the calculation of cyclic stresses and strains are obtained with the four-point correlation method. The mesoscopic models of different zones are inserted into the joint macroscopic model as submodules. The models containing the information of hardening particles and grain orientation are established with crystal plasticity theory for the grains and isotropic hardening rule for the hardening particles. The effects of hardening particles and grain orientation on the stress and strain responses are discussed. The simulation results show that high-angle misorientation of adjacent grains hinders the stress transfer. The particle cluster or cracked particles intensify the stress and strain concentrations.

Research on the Properties and Low Cycle Fatigue of Sc-Modified AA2519-T62 FSW Joint

“…The obtained value of the cyclic strength coefficient (504.37 MPa) is almost three times lower than for the base material (1518.1 MPa) [ 52 ]. Although, the decrease of cyclic strength coefficient is expected for welded joints, in this case, the reported drop is significant and the obtained value is similar to the values reported by research [ 31 , 36 , 55 , 56 , 57 ]. In the next step, the parameters of the stabilized loops were used for establishing the plots of elastic and plastic strain amplitudes vs. number of reversals, presented in Figure 15 .…”

Microstructure and Low Cycle Fatigue Properties of AA5083 H111 Friction Stir Welded Joint

“…Therefore, cyclic deformation characteristics and fatigue of the friction stir welded joints must be ascertained to guarantee the structural integrity and safe use, e.g., under the influence of impulsive pressure loads due to slamming. There have been some reports on the fatigue properties of FSW joints of heat treated [15] or numerically analyzed [16] aluminum alloys. However, previous studies focused mainly on the fatigue life [17,18] and crack growth [19][20][21], with only limited studies on the low-cycle fatigue (LCF) behavior of FSW joining in aluminum alloys [22][23][24].…”

Fatigue Damage Evaluation of Aviation Aluminum Alloy Based on Strain Monitoring

“…Realizing the correlation between fine-scale deformation mechanisms and macroscopic mechanical behavior is crucial in the field of crystal plasticity mechanics, particularly in the study of fatigue in polycrystalline alloys [17][18][19][20][21][22][23][24][25][26]. For instance, Takayuki Shiraiwa [17] incorporated computed local plastic strain into the quasi-measurement of crack initiation to predict the fatigue life of 7075 aluminum alloy.…”

“…For instance, Takayuki Shiraiwa [17] incorporated computed local plastic strain into the quasi-measurement of crack initiation to predict the fatigue life of 7075 aluminum alloy. Sun [21] investigated the influence of grain orientation and hardened particles on the fatigue performance of friction stir welded (FSW) joints in aluminum alloys. In these studies [18][19][20][23][24][25], the prediction of metal fatigue life primarily involved exploring new fatigue indicating factors (FIPS).…”