Finite element simulations and experimental verifications for forming limit curve determination of two-layer aluminum/brass sheets considering the incremental forming process

In this paper, forming limit diagram (FLD) of aluminum/brass two-layer sheets through an incremental forming process (ISF) was studied numerically and experimentally. At first, the two-layer aluminum 1050/brass (65% copper) sheets were fabricated using the roll bonding process. Also, the finite element simulations of the incremental forming process with ABAQUS software were utilized to predict the FLD. For this purpose, the criterion of the second derivative of the equivalent plastic strain was used to predict fracture. Finally, the numerical simulation results were compared with the experimental results. For instance, comparing experimental and numerical FLD0 values for the formed samples with forming angle 62.5-degree showed a 7% difference. However, the difference was negligible, and numerical simulation results could be used with an appropriate reliability coefficient. The effect of sheet arrangement towards tools was then investigated. It finds out from the experimental results that the formability of the Brass/Al (brass was up layer and aluminum was bottom layer) was more than the Al/Brass (aluminum is up layer and brass is bottom layer). In the following, the ISF parameters such as forming limit angle, step-down, and thickness distribution were investigated.

Finite Element Modeling and Mechanical Testing of Metal Composites Made by Composite Metal Foil Manufacturing

Foils of aluminum 1050 H14 ½ hard temper and 99.9% copper with 500-micron thickness have been used to manufacture similar and dissimilar composites by composite metal foil manufacturing (CMFM). The metal foils are bonded to each other using a special 80% zinc and 20% aluminum by weight brazing paste. A 3D finite element model has been developed to numerically analyze the time required to heat the metal foils so that a strong bond can be developed by the paste. The numerical simulations run in ANSYS 19.1 have been validated through experiments and rectangular layered composite products have been developed for flexural testing. The flexural test results for layered Al and Al/Cu composites are compared with solid samples of Al 1050 and 99.9% pure copper made by subtractive method. The results show that the layered Al composite is 5.2% stronger whereas the Al/Cu sample is 11.5% stronger in resisting bending loads compared to a solid Al 1050 sample. A higher bend load indicates the presence of a strong intermetallic bond created by the brazing paste between the metal foils. Corrosion testing was also carried out on the composite samples to assess the effect of corrosion on flexural strength. The tests revealed that the composites made by CMFM are not affected by galvanic corrosion after 7 days of testing and the flexural loads remained consistent with composites that were not immersed in a solution of distilled water and NaCl.

Formability Analyses on Single Point Incremental Sheet Forming Process on Aluminum 1050

In recent years, there is a lot of demand on metal forming processes in which sheet metal forming process has lots of applications in the automotive and aerospace industries. In sheet metal forming operations, incremental forming is an emerging technology in which, single point incremental forming (SPIF) process is die-less in incremental forming process and providing a competitive alternative to economical and effective in fabricating low volume products. The objective of this work is to analyze the forming analysis on truncated pyramid product by avoiding cracking and maintaining the optimum forming conditions. The formability is analyzed by using ABAQUS software and simulation, different process parameters were varied such as sheet thickness, tool diameter, step depth, spindle rotational speed on aluminum AA1050 alloy. From the simulation results, stress stain and stain distribution were evaluated on the deformed sheet. The product produced is truncated pyramid dimension having square base of side and fillet at corner.

Novel Method of Severe Plastic Deformation - Continuous Closed Die Forging: CP Aluminum Case Study

There is a large number of methods for severe plastic deformation (SPD). Multidirectional forging (MDF) is probably one of the most easily scalable for industrial application. In general, two main conditions need to be fulfilled for successful SPD processing: constant sample geometry and application of a quasi-hydrostatic pressure. The first condition is necessary for strain accumulation by repetitive deformation and the second one helps preventing cracking in the specimens with high accumulated strain. However, MDF is not providing quasi-hydrostatic condition in the processed sample. This paper reports a novel method for severe plastic deformation, namely continuous closed die forging (CCDF), which fulfils both requirements for the successful deformation of samples to a very high accumulated strain. Commercially pure aluminum (1050) was processed to a total strain of 24 by CCDF. After processing, the microstructure was refined down to a mean grain size of 0.78 μm. Tensile testing showed good mechanical properties: yield strength and ultimate tensile strength of the ultrafine-grained aluminum were 180 and 226 MPa, respectively. Elongation to rupture was about 18%. The microstructure, microhardness and grain boundary statistics are discussed with regard to the high mechanical properties of the UFG aluminum processed by this novel method.

Effect of Equal Channel Angular Pressing on Different Face Center Cubic (FCC) Metals

Equal channel angle pressing (ECAP) of commercial purity aluminum (1050), oxygen free high conductivity copper (OFHC Cu) and high purity tin (99,99% Sn) were conducted using C processing route. The variation of microstructure, of micro-Vickers hardness and of macroscopic material parameters with number of pressings was documented up to ten passes. Tensile tests were used to evaluate post ECAP deformation response. Optical microscope was used to obtain statistical information on the microstructure developed during ECAP. The present results showed that, as it can be found in the literature, first ECAP pass has resulted in enhancement of mechanical properties. Further ECAP processing, as original observation, has resulted in slight improvement and after ~7 pressing decreasing of hardness can be observed. The true stress–strain curve for ECAP-ed specimens tested under tension showed the evolution of macroscopic material properties is similar. This behavior can be connected with the deformation microstructure of the specimen, grain deformation and fragmentation.