Evolution mechanisms of microstructure and mechanical properties in a friction stir welded ultrahigh-strength quenching and partitioning steel

2022 ◽  
Vol 102 ◽  
pp. 213-223
Author(s):  
Z.W. Wang ◽  
J.F. Zhang ◽  
G.M. Xie ◽  
L.H. Wu ◽  
H. Zhang ◽  
...  
Vacuum ◽  
2021 ◽  
Vol 188 ◽  
pp. 110216
Author(s):  
Taher A. Shehabeldeen ◽  
Nagi M. El-Shafai ◽  
Ibrahim M. El-Mehasseb ◽  
Yajun Yin ◽  
Xiaoyuan Ji ◽  
...  

Silicon ◽  
2021 ◽  
Author(s):  
K. S. Ashraff Ali ◽  
V. Mohanavel ◽  
M. Ravichandran ◽  
S. Arungalai Vendan ◽  
T. Sathish ◽  
...  

Metals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1097
Author(s):  
Umer Masood Chaudry ◽  
Seung-Chang Han ◽  
Fathia Alkelae ◽  
Tea-Sung Jun

In the present study, the effect of post-weld heat treatment (PWHT) on the microstructure and mechanical properties of friction stir welded (FSW) DP780 steel sheets was investigated. FSW was carried out at a constant tool rotation speed of 400 rpm and different welding speeds (200 mm/min and 400 min/min). A defect free weld was witnessed for both of the welding conditions. The mutual effect of severe plastic deformation and frictional heat generation by pin rotation during the FSW process resulted in grain refinement due to dynamic recrystallization in the stir zone (SZ) and thermo-mechanically affected zone (TMAZ). Lower tensile elongation and higher yield and ultimate tensile strengths were recorded for welded-samples as compared to the base material (BM) DP780 steel. The joints were subsequently annealed at various temperatures at 450–650 °C for 1 h. At higher annealing temperature, the work hardening rate of joints gradually decreased and subsequently failed in the softened heat-affected zone (HAZ) during the uniaxial tensile test. Reduction in yield strength and tensile strength was found in all PWHT conditions, though improvement in elongation was achieved by annealing at 550 °C. The digital image correlation analysis showed that an inhomogeneous strain distribution occurred in the FSWed samples, and the strain was particularly highly localized in the advancing side of interface zone. The nanoindentation measurements covering the FSWed joint were consistent with an increase of the annealing temperature. The various grains size in the BM, TMAZ, and SZ is the main factor monitoring the hardness distribution in these zones and the observed discrepancies in mechanical properties.


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