Mechanical properties and microstructure of Ti6321 titanium alloy welded joints at high temperature and medium strain rate
The Gleeble thermal simulation testing machine was used to conduct high-temperature and me-dium strain rate compression tests on different areas of the welded joint.The impact of the structure of dif-ferent areas of the welded joint on its mechanical properties was studied,and the effects of temperature and strain rate on its deformation process were analyzed.The results show that during medium strain rate compression at high temperatures,the heat affected zone exhibits the highest strength,followed by the base metal and the weld metal with relatively lower strength.At high temperatures(350℃ & 550℃),as the strain rate increases(1 s-1 & 10 s-1),the dominant factor in deformation changes from the strain hardening effect to the thermal softening effect.At 350℃,as the strain rate increases,the strength in-creases;at 550℃,as the strain rate increases,the strength decreases.The base metal has low adiabatic shear sensitivity,and a large range of grain coordinated deformation occurs along the direction of maximum shear stress during the process.Since the microstructure of the heat affected zone is uniform,the increase in strain rate relative to the increase in temperature can promote the generation of adiabatic shear bands in the heat affected zone.When the weld metal is compressed,stress tends to concentrate at the grain boundaries,and the temperature at this time is more favorable for the generation of adiabatic shear bands during compression deformation.
Ti6321 titanium alloywelded jointhigh temperature and medium strain rateadiabatic shear
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