Influence of different rolling routes on mechanical anisotropy and formability of commercially pure titanium sheet

Influence of three different rolling routes on mechanical anisotropy and formability of commercially pure titanium sheetwas investigated.Route A and Route B are unidirectional rolling(UR)where the rolling direction is along initial rolling direction(RD)and transverse direction(TD),respectively.Route C is cross rolling(CR)where the rolling direction is changed by90°aftereach rolling pass.The microstructure and texture,tensile mechanical properties including strength and elongation,and also theanisotropy of the UR and CR sheets were investigated at room temperature.The XRD results indicate that the texture intensity ofrolled samples gradually weakens from Route A to Route C.Compared with Route A and Route B rolled samples,the Route C rolledsamples show a smaller planar anisotropy.The deep drawing tests reveal that cross rolling can avoid the occurrence of earing.Erichsen tests indicate that rolling routes have an effect on stretch formability of pure titanium sheet.

Microstructure and formability evolutions of AZ31 magnesium alloy sheets undergoing continuous bending process

Continuous bending (CB) process along rolling direction was performed to improve the formability of AZ31 magnesium alloy sheets. The microstructure and texture evolutions were characterized by optical microscopy (OM) and electronic backscatter diffraction (EBSD). The results reveal that the basal texture intensity of continuously bent and annealed (CBA) sample is drastically weakened. A large number of twins are induced on the concave surface by the 1st pass bending and the density of twins obviously declines during the 2nd pass bending owing to the occurrence of detwinning. Due to the asymmetric tension?compression strain states between the outer and inner regions during V-bending, twinning and detwinning are generated alternatively during the CB process. The Erichsen value is 5.2 mm which increases by 41% compared with that of as-received sample. This obvious improvement of formability can be attributed to the weakened basal texture, which leads to a smaller plastic strain ratio (r-value)together with a larger strain-hardening exponent (n-value).

Influence of Grain Orientation on the Corrosion Behavior of Rolled AZ31 Magnesium Alloy

The effect of the grain orientation on corrosion behavior of rolled AZ31 magnesium alloy is investigated in this study. The test samples have a similar surface roughness to the Mg alloy in practical application. The immersion test and electrochemical impedance spectroscopy show that the TD-ND planes dominated by （101-0）, （1120） and （1011） oriented grains show a higher corrosion resistance compared with these of the RD-TD planes which consist mainly of （0001） oriented grains. Here, RD, ND and TD represent the rolling direction, the normal direction and the transverse direction of the alloy sheet, respectively. The surface morphologies of the alloys at various immersion stages are observed by scanning electron microscopy, and the surface topography of the alloy substitutes is also observed by laser scanning confocal microscopy. The TD-ND planes show a regular corrosion along the TD direction, but the RD-TD plane shows an irregular corrosion.

Influence of Continuous Bending Process on Texture Evolution and Mechanical Properties of AZ31 Magnesium Alloy

Mg-3Al-lZn alloy sheets have been deformed by continuous bending（CB）to investigate the effects of pro-cessing parameters（bending angle and repetitive passes）on the texture and formability.The samples exhibited a bimodal microstructure with abnormal growth grains in the surface region and fine grains distributed in the center after CB process followed by annealing.The texture evolution measured by XRD indicated that the basal poles were rotated from ND toward RD,and the texture intensity decreased with the bending angle decreasing and repetitive passes increasing.Compared with the as-received sample,the yield strength of CBA-120-2 sample significantly decreased from 183 to 112 MPa,and a smaller r-value and a larger n-value were obtained.The formability of CB processed samples in annealing condition was significantly enhanced with the highest of Erichsen value of 5.4 mm,increased by about 135%.The improvement of formability was likely attributed to the weakened and RD-tilt basal texture and coarse grains in the surface part.

Microstructure and corrosion properties of Mg-0.5Zn-0.2Ca-0.2Ce alloy with different processing conditions

The microstructure and corrosion resistance of Mg-0.5 Zn-0.2 Ca-0.2 Ce alloy with different processing conditions were investigated.The composition was detected by X-ray fluorescence(XRF),and the microstructure was analyzed by optical microscopy(OM)and scanning electron microscope(SEM)equipped with energy-dispersive spectroscopy(EDS).The corrosion behavior was investigated by hydrogen evolution tests,weight loss tests and electrochemical measurements.The Mg-0.5 Zn-0.2 Ca-0.2 Ce alloy has much better corrosion resistance compared with the commercial AZ31 sheet,which can be attributed to its dispersive second phases and protective corrosion products film on the alloy surface.Moreover,the as-rolled Mg-0.5 Zn-0.2 Ca-0.2 Ce alloy shows much better corrosion resistance compared with the as-extruded Mg-0.5 Zn-0.2 Ca-0.2 Ce alloy.This can be due to three aspects:The as-rolled alloy has smaller grain size;the as-rolled alloy has lower(1010)/(1120)texture intensity;the residual stress of the as-rolled alloy is eliminated during the annealing process,but large residual stress exists in the asextruded alloy produced by the extrusion process.