**7. Summary**

*Aluminium Alloys and Composites*

bulged portion of the tube [64].

**6. Aluminum alloy behavior during bi-axial forming**

fracture by altering the location of the greatest thinning [65].

increase value is sensitive to the strain path [66].

The Gurson-Tvergaard-Needleman (GTN) damage model combined with the finite element method was used to investigate the influence of double-sided pressure on the deformation behavior of biaxially stretched AA6111-T4 sheet metal. The Marciniak-Kuczynski (M-K) localized necking model was used to predict the right-hand side of the forming limit diagram (FLD) of sheet metal under superimposed double-sided pressure. The forming limit curve (FLC) of the biaxially stretched AA6111-T4 sheet metal under the superimposed double-sided pressure had improved and the fracture locus shifts to the left. Besides, the formability

Through the numerical biaxial tensile tests of the sheet, the biaxial tensile deformation behavior of 5182 aluminum alloy sheet was predicted. From the numerical simulations, the stress-strain curves and the shapes of the contours of plastic work were calculated and were quantitatively verified by the experimental biaxial tensile test using the cruciform specimen. Using the results of experimental and numerical

the tensile load along plane direction in the same time.

hydroforming analysis was made on extruded aluminum tubular specimen made up of AA 6063 alloy bulged from the diameter of 38–54 mm. The thickness distribution at bulging the region along lateral and longitudinal directions was analyzed. The parameters considered are axial feed, tube thickness, fluid pressure, and die semi-cone angle. The forming characteristics such as thickness distribution and bulged diameter were studied using toolmaker microscope and coordinate measuring machine. Maximum shear thinning is observed in the largest diameter of the

Here, some of the recent discussions are made based on the bi-axial forming process. It is also treated as a stretching process in which sheet material experiences

Biaxial warm forming behavior in the temperature range 200–350°C was investigated for three aluminum sheet alloys: Al 5754, Al 5182, and Al 6111-T4. The formability for all the three alloys improved at elevated temperatures; the strain hardened alloys Al 5754 and Al 5182 showed considerably greater improvement than the precipitation hardened alloy Al 6111-T4. Formability was studied by forming rectangular parts at a rapid rate using internally heated punch and die in both isothermal and nonisothermal conditions. The temperature effect on drawing of the sheet was found to have a large effect on formability. FLD under warm forming conditions was also determined, which showed results that are consistent with the evaluation of part depth. Biaxial forming behavior was investigated for three aluminum sheet alloys of Al 5182, Al 5754, and 6111-T4 using a heated die and punch in the warm forming temperature range of 200–350°C. It was found that all three alloys exhibited significant improvement in the formability compared with that at room temperature. The nonheat-treatable alloys of AA 5182 and AA 5754 showed a higher part depth than that of heat-treatable 6111-T4. The formidability characteristic was dependent on the blank holding pressure (BHP). When the BHP decreased, the formability increased, but increasing the forming temperature and/ or BHP minimizes the wrinkling tendency and improves the forming performance. By increasing temperature and BHP, the stretchability of the sheet alloys was increased. Through setting the temperature 50°C higher than the punch temperature to enhance the drawing component, the optimum formability was achieved. Strain distribution was also improved with setting the die temperature higher than the punch temperature in a part in such a manner that postpones necking and

**162**

Forming behavior of different aluminum alloys is discussed in the above sections. The forming processes considered included the hot forming process, deep drawing process, incremental process, hydroforming process, and bi-axial forming. The effect of their parameters on aluminum alloys is realized. From each forming process and test, the forming limit strain is determined to quantify the formidability of each aluminum alloy. Moreover, the quantification of the formability of Al alloys can help the industries.
