Tensile and Fatigue Analysis Based on Microstructure and Strain Distribution for 7075 Aluminum FSW Joints

In order to study on tensile and fatigue fracture mechanism of friction stir welded (FSW) joints, the tensile and fatigue behavior of FSW joints are studied based on the microstructure and strain distribution. The large plastic deformation and fracture occurred in the thermo-mechanically affected zone (TMAZ) on retreating side in tension tests. High contents of shear texture and small angle grain boundary reduce the tensile mechanical property of TMAZ material. The fatigue weak area for FSW joints is affected by the loading condition. The strain concentration in the welded nugget zone (WNZ) and base material makes the fatigue fracture liable to happen in these areas for the FSW joints under the stress ratios of 0.1 and −0.3. When the fracture occurred in WNZ, the crack initiation mainly occurred in clusters of hardened particles, while when the fracture happened in base material, the crack initiation mainly occurred near the pit. The crack in WNZ propagated in an intergranular pattern and the crack in the other areas extended in a transgranular mode, leading to a higher crack growth rate of WNZ than of other regions.

[1]  B. Tang,et al.  The effects of grain morphology and crystallographic orientation on fatigue crack initiation in a metastable β titanium alloy Ti-7333 , 2020 .

[2]  Qingyuan Wang,et al.  Effect of texture and banded structure on the crack initiation mechanism of a friction stir welded magnesium alloy joint in very high cycle fatigue regime , 2020 .

[3]  A. Ranjan,et al.  Recent research progress in solid state friction-stir welding of aluminium–magnesium alloys: a critical review , 2020 .

[4]  F. Cortial,et al.  Fatigue behavior of FSW high-yield strength steel welds for shipbuilding application , 2019, Welding in the World.

[5]  M. Besel,et al.  Heterogeneous local straining behavior under monotonic and cyclic loadings in a friction stir welded aluminum alloy , 2019, International Journal of Fatigue.

[6]  E. Ghassemali,et al.  The effect of Fe-rich intermetallics on crack initiation in cast aluminium: An in-situ tensile study , 2019, Materials Science and Engineering: A.

[7]  R. R. McCullough,et al.  Fatigue crack nucleation and small crack growth in an extruded 6061 aluminum alloy , 2019, International Journal of Fatigue.

[8]  H. Remes,et al.  Full-field Strain Measurements for Microstructurally Small Fatigue Crack Propagation Using Digital Image Correlation Method. , 2019, Journal of visualized experiments : JoVE.

[9]  D. Shang,et al.  Study on small fatigue crack initiation and growth for friction stir welded joints , 2019, Materials Science and Engineering: A.

[10]  Xinjiang Fei,et al.  Research of temperature and microstructure in friction stir welding of Q235 steel with laser-assisted heating , 2018, Results in Physics.

[11]  N. Vanderesse,et al.  Fatigue performances of FSW and GMAW aluminum alloys welded joints: Competition between microstructural and structural-contact-fretting crack initiation , 2018, International Journal of Fatigue.

[12]  Jun Dong,et al.  Determination of the local constitutive properties of the welded steel joints using digital image correlation method , 2018 .

[13]  Shujun Chen,et al.  Effect of non-axisymmetric arc on microstructure, texture and properties of variable polarity plasma arc welded 5A06 Al alloy , 2018 .

[14]  M. Ramulu,et al.  Friction stir welding of titanium alloys: A review , 2018 .

[15]  Yong Liu,et al.  Correlation between micro-mechanical property and very high cycle fatigue (VHCF) crack initiation in friction stir welds of 7050 aluminum alloy , 2017 .

[16]  G. Epasto,et al.  Fatigue analysis of marine welded joints by means of DIC and IR images during static and fatigue tests , 2017 .

[17]  M. Besel,et al.  Influence of local fatigue damage evolution on crack initiation behavior in a friction stir welded Al-Mg-Sc alloy , 2017 .

[18]  R. Fu,et al.  A study on microstructure and mechanical properties of AA 3003 aluminum alloy joints by underwater friction stir welding , 2017 .

[19]  Liang-ming Yan,et al.  In-situ SEM study of fatigue crack initiation and propagation behavior in 2524 aluminum alloy , 2016 .

[20]  F. Shen,et al.  Effect of grain size on the fatigue crack growth behavior of 2524-T3 aluminum alloy , 2016 .

[21]  C. Deng,et al.  Effects of microstructural heterogeneity on very high cycle fatigue properties of 7050-T7451 aluminum alloy friction stir butt welds , 2016 .

[22]  Guoqing Wang,et al.  Determination of local constitutive behavior and simulation on tensile test of 2219-T87 aluminum alloy GTAW joints , 2015 .

[23]  V. Balasubramanian,et al.  Fatigue crack growth behaviour of friction stir welded AA7075-T651 aluminium alloy joints , 2014 .

[24]  W. Kim,et al.  Texture and microstructure evolution and mechanical properties during friction stir welding of extruded aluminum billets , 2014 .

[25]  Z. Yue,et al.  Finite element simulation of surface deformation of polycrystal with a rough surface under repeated load , 2012 .

[26]  V. Balasubramanian,et al.  Correlation between weld nugget grain size, weld nugget hardness and tensile strength of friction stir welded commercial grade aluminium alloy joints , 2012 .

[27]  P. Wanjara,et al.  Effect of welding parameters on microstructure and mechanical properties of AA7075‐T6 friction stir welded joints , 2011 .

[28]  P. Gougeon,et al.  Effect of the surface preparation techniques on the EBSD analysis of a friction stir welded AA1100-B4C metal matrix composite , 2011 .

[29]  T. Zhai,et al.  The behavior of fatigue crack initiation and propagation in AA2524-T34 alloy , 2011 .

[30]  M. Liao.  Probabilistic modeling of fatigue related microstructural parameters in aluminum alloys , 2009 .

[31]  Omar Hatamleh,et al.  Effects of peening on mechanical properties in friction stir welded 2195 aluminum alloy joints , 2008 .

[32]  Pierre Vacher,et al.  Comparative study on local and global mechanical properties of 2024 T351, 2024 T6 and 5251 O friction stir welds , 2006 .

[33]  Yutaka S. Sato,et al.  Effect of micro-texture on fracture location in friction stir weld of Mg alloy AZ61 during tensile test , 2003 .

[34]  B. M. Hillberry,et al.  Effects of constituent particle clusters on fatigue behavior of 2024-T3 aluminum alloy , 1998 .

[35]  A. Merati.  A study of nucleation and fatigue behavior of an aerospace aluminum alloy 2024-T3 , 2005 .

[36]  James C. Newman,et al.  An empirical stress-intensity factor equation for the surface crack , 1981 .