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In this study, a new method is proposed to determine limit strains at the onset of localized necking for ductile materials that show post-uniform elongations. The new method is first applied for AA 5754-O using the ISO 12004-2 forming limit diagram determination standard. The method is also applied for ductile materials of 7114 steel, 304 stainless steel, and CuZn37 brass and finally for AA 2024-T4 having brittle fracture behavior. The results indicate that the new proposed method is quite successful, easy, and accurate for ductile materials that show post-uniform elongations.

Temperature is the main effective process parameter in the warm deep drawing (WDD) process to improve the formability of light-weight engineering materials, and this feature requires the accurate measurement and assessment of temperature for process stability. In this study, an evaluation of the WDD process was conducted according to the forming temperature curves (FTCs) characterized from work piece temperatures instead of tool temperatures, as usual. To achieve this goal, a special index material was developed to accurately obtain FTCs from the work piece material under closed and heated tool conditions. The differences of temperature on work piece material are required to define temperatures by curves. The characteristic behavior of these curves was investigated under non-isothermal WDD of AA 5754-O. In the experimentation stage, the process parameters, namely FTC, blank holder force and punch velocity, which assure successful deep drawability, were determined according to the failure-free cups by analyzing wrinkling and tearing conditions and minimum cup height parameters as output parameters. As the next step, optimum conditions were investigated by evaluating the cup volume and springback parameters. As a general conclusion, approximately 330 • C in the flange-die radius region and 100 • C in the cup wall-punch bottom region are the ideal optimum temperatures for the warm deep drawing process.

Aluminum alloys have good properties such as high strength-to-weight ratio, corrosion resistance and relatively low cost. Nowadays they are primarily used as wrought and cast in many industries such as automotive, aviation and aerospace because of these properties. Aluminum alloys are classified into two categories as non-heat-treatable and heat-treatable. The mechanical properties of the heat-treatable alloys are improved by solution heat treatment and controlled ageing. While mechanical properties of some heat-treatable alloys, especially 2XXX series, become stable with natural ageing at room temperature within a few days, some of them are unstable and exhibit significant changes in properties even after many years. Heat treatment process of AA 2024 is very sensible and critical and therefore should be carefully performed. In this research, effects of the solution temperature, soaking time, heating rate and quenching delay condition of AA 2024 on the mechanical properties were investigated.