Microstructure and Texture Inhomogeneity after Large Non-Monotonic Simple Shear Strains: Achievements of Tensile Properties

Abstract

Abstract:In this study, for the first time, the effect of large non-monotonic simple shear strains on the uniformity of the tensile properties of pure Cu specimens was studied and justified by means of microstructural and textural investigations. A process called simple shear extrusion, which consists of two forward and two reversed simple shear straining stages on two different slip planes, was designed in order to impose non-monotonic simple shear strains. Although the mechanism of grain refinement is continuous dynamic recrystallization, an exceptional microstructural behavior and texture were observed due to the complicated straining path results from two different slip planes and two pairs of shear directions on two different axes in a cycle of the process. The geometry of the process imposes a distribution of strain results in the inhomogeneous microstructure and texture throughout the plane perpendicular to the slip plane. Although it is expected that the yield strength in the periphery reaches that of the center by retardation, it never reaches that value, which results in the different deformation modes of the center and the periphery. The occurrence of shear reversal in each quarter of a cycle results in the elimination of some of the boundaries, an increase in the cell wall thickness, and a decrease in the Taylor factor. Change in the shear plane in each half of a cycle leads to the formation of cell boundaries in a different alignment. Since the direction of the shear and/or the shear plane change frequently in a cycle, the texture of a sample after multi-cycles of the process more closely resembles a random orientation.

On the Production of Severely Deformed Workpieces in Large Scales: A Step Towards Industrialization

“…Small deviations between the parameters may have originated for three reasons: first, the sample preparation conditions, especially the region from which the sample is extracted, where a small change in place may result in a difference in ; second, from the different lengths of the deformation channels, which, in turn, result in different strain reversal behaviour. 34,36,49 Figure 7 shows transmission electron micrographs of the deformed workpieces viewed from the ED plane and taken from the central region of the samples. For the samples deformed by FIC and MIC dies, the microstructure after the first pass of SSE consists of strongly elongated subgrains with mean lamellar boundary (LBs) spacing of 710 þ23 À21 nm and 706 þ25…”

Microstructure and Mechanical Properties of Low-Carbon High-Strength Steel Fabricated by Wire and Arc Additive Manufacturing

“…where σ is the applied stress; M is Taylor factor; and τ c is the critical resolved shear stress on each of the activated slip systems [39]. The comparison results of the Taylor factor distribution are shown in Figure 17.…”

Processing–Structure–Property Relationships in Metals

“…The book gathers manuscripts from academic and industrial researchers with stimulating new ideas and original results. It consists of one review paper regarding state of art and perspectives of alloys for aeronautic applications [1] and fifteen research papers [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] focused on different materials and processes.…”

“…A group of papers deals with the effect of ultra-fine or nanostructured grains on the mechanical properties, the materials are: a low-carbon steel processed by cryorolling [2], Mg-10Y-6Gd-1.5Zn-0.5Zr alloy submitted to two different heat treatments [3], AZ91 Mg alloy prepared by ECAP plus aging [4], hard nanostructured coatings deposited on a S600 high speed steel [5], and pure Cu deformed by simple shear extrusion, namely two forward and two reversed simple shear straining stages on two different slip planes [6]. The different routes used to produce ultra-fine or nanostructured grains introduce a variety of microstructures in terms of: (i) dislocation density and arrangement; (ii) size and orientation distribution of the grains; and (iii) size, shape, and fraction of secondary phases.…”