M. Tkocz

Application of Incremental Metal Forming for Production of Aircraft Integral Panels

The principle and the potential of an incremental bulk metal forming method is presented in the paper. It can be used for manufacturing of the specific aircraft integral panels in a form of ribbed parts with high surface/thickness ratio. A unique laboratory device has been developed to investigate the effect of process parameters on the material flow and the press load. It utilizes tooling consisting of working rolls, a die and a punch that is divided into a number of segments. The results of preliminary numerical simulations proved that the presented forming method offers significant advantages in comparison with conventional forging.

Numerical and Experimental Investigation of the Innovatory Incremental-Forming Process Dedicated to the Aerospace Industry

The main goal of this work is development of the incremental-forming (IF) process for manufacturing integral elements applicable to the aerospace industry. A description of the proposed incremental-forming concept based on division of large die into a series of small anvils pressed into the material by a moving roll is presented within this article. A unique laboratory device has been developed to investigate the effects of process parameters on the material flow and the press loads. Additionally, a developed numerical model of this process with specific boundary conditions is also presented and validated to prove its predictive capabilities. However, main attention is placed on development of the process window. Thus, detailed investigation of the process parameters that can influence material behavior during plastic deformation, namely, roll size and roll frequency, is presented. Proper understanding of the material flow to improve the IF process, as well as press prototype, and to increase its technological readiness is the goal of this article. Results in the form of, e.g., strain distribution or recorded forging loads are presented and discussed.

The Potential and Application Areas of Forging Aided by Shear Stress

The paper demonstrates the potential of unconventional metal forming method that consists in introducing shear stress at the die/workpiece interface during compression. In practice it can be realized by induction of reciprocating, vertical motion of a punch that adheres strongly to a workpiece. To estimate an effect of the method on the material flow, a relevant finite element model has been developed and the selected results of numerical simulations are presented in the paper. In comparison to the conventional forging, forming aided by shear stress is able to provide a number of benefits such as significant increase of local strains, lower press loads and the opportunity to control the strain distribution in the workpiece volume. Perspectives for continuation of the studies as well as possible application areas of forging aided by shear stress are discussed in the summary.

The Effect of Compression Aided by Additional Shear Stress on Microstructure of Composites Reinforced with Ceramic Particles

The paper presents a new method for processing of cast composites reinforced with ceramic particles in order to improve the microstructure homogeneity and material properties. The presented forming method consists in compression aided by additional shear stress that is caused by transverse motion of a punch. As a result, severe plastic deformation can be obtained in a workpiece. A series of experiments was conducted for previously cast Al-Mg-Cu matrix composites containing 15% reinforcement in a form of the mixture of SiC and glassy carbon particles. It was found that the applied method allows to refine the particles and to obtain a good-quality bonding on the particle-matrix interface.

Estimation of Flow Stress of Zinc-Titanium Strip during Reverse Rolling

Due to some specific features (high corrosion resistance and long-life durability in particular) as well as interesting aesthetic appeal, zinc-titanium strips are widely used as roof coverings, facade panels and rain gutters. The Zn-Ti strips are manufactured either in the hot rolling lines or in the reverse rolling mills at elevated temperatures. A problem of determination the average flow stress of zinc-titanium strip in the latter mentioned technology and in the actual rolling conditions is discussed in the paper. The analysis is based on the results of plastometric compression tests, FEM simulations and industrial practice.

Deformation-Induced Grain Refinement in AlMg5 Alloy

The results presented in this paper are concerned with the microstructure and the mechanical properties of the AlMg5 alloy subjected to severe plastic deformation by multiple compression in two orthogonal directions. Four experiments with an increasing number of passes were conducted on the Gleeble MAXStrain system in order to obtain various effective strain levels. The deformed microstructure was investigated by means of the light microscopy (LM) and the scanning transmission electron microscopy (STEM). The mechanical properties were determined for the most deformed, central parts of samples. Investigations revealed that severe cold deformation of the AlMg5 alloy leads to strong grain refinement. Moreover, fragmentation of large intermetallic inclusions and their regular distribution were obtained in the analysed, central parts of the samples. Microstructural changes led to significant improvement in the strength properties. After reaching the effective strain of 9, the AlMg5 alloy exhibited UTS, YS and HV values almost two times higher than corresponding values determined for the starting, annealed material.