High Temperature Deformation Behavior and Microstructure Evolution of Low-Density Steel Fe30Mn11Al1C Micro-Alloyed with Nb and V

The thermal processing parameters is very important to the hot rolling and forging process for producing grain refinement in lightweight high-manganese and aluminum steels. In this work, the high temperature deformation behaviors of a low-density steel of Fe30Mn11Al1C alloyed with 0.1Nb and 0.1V were studied by isothermal hot compression tests at temperatures of 850–1150 °C and strain rates between 0.01 s−1 and 10 s−1. It was found that the flow stress constitutive model could be effectively established by the Arrhenius based hyperbolic sine equation with an activation energy of about 389.1 kJ/mol. The thermal processing maps were developed based on the dynamic material model at different strains. It’s shown that the safe region for high temperatures in a very broad range of both deformation temperature and deformation strain and only a small unstable high deformation region, located at low temperatures lower than 950 °C. The deformation microstructures were found to be fully recrystallized microstructure in the safe deformation region and the grain size decreases along with decreasing temperature and increasing strain rate. Whereas the deformation microstructures is composed by grain refinement-recrystallized grains and a small fraction of non-recrystallized microstructure in the unstable deformation region, indicating that the deformation behaviors controlled by continuous dynamic recrystallization. The Hall Petch relationship between microhardness and the grain size of the high temperature deformed materials indicates that high strength low-density steel could be developed by a relative low temperature deformation and high strain rate.

Shape Analysis of the Elastic Deformation Region throughout the Axi-Symmetric Wire Drawing Process of ETP Grade Copper

The wire drawing process is commonly perceived as one of the best studied metal forming processes in almost every aspect; however, when considering elastic deformation, researchers usually focus on the uniaxial tensile forces after the material exits the drawing die and not the elastic deformation region before entering the drawing die, even though it may have a significant impact on the strength parameters and the nature of metal flow inside the drawing die. The aim of this research is to theoretically and experimentally identify the deformation in the elastic region and to further link the shape of this region and the values of stress occurring in it with the geometrical parameters of the drawing process and assess its impact on its strength parameters. In order to achieve the assumed goals, numerical analyses using the finite element method and experimental research on the drawing process in laboratory conditions were carried out using Vickers hardness tests and resistance strain gauges measuring deformation in stationary and non-stationary conditions. The obtained results indicate that the shape and the extent of the region of elastic deformations generated in the material before the plastic deformation region during the drawing process depends on the applied deformation coefficient and stationarity of the process.

The Central Strain Analytical Modeling and Analysis for the Plate Rolling Process

The strain after rolling plays an important role in the prediction of the microstructure and properties and plate deformation permeability. So it is necessary to establish a more accurate theoretical strain model for the rolling process. This paper studies the modeling method of the equivalent strain based on the upper bound principle and stream function method. The rolling deformation region is divided into three zones (inlet rigid zone, plastic zone, and outlet rigid zone) according to the kinematics. The boundary conditions of adjacent deformation zones are modified according to the characteristics of each deformation zone. A near-real kinematics admissible velocity field is established by the stream function method on this basis. The geometric boundary conditions of the deformation region are obtained. The deformation power, friction power and velocity discontinuous power are calculated according to the redefined geometric boundary conditions. On this basis, the generalized shear strain rate intensity is calculated according to the minimum energy principle. Finally, the equivalent strain model after rolling is obtained by integrating the generalized shear strain rate in time. The plate rolling experiments of AA1060 and the numerical simulations are carried out with different rolling reductions to verify the analytic model precision of the equivalent strain. The results show that the minimum and maximum relative equivalent strain deviation between the analytic model and the experiment is 0.52% and 9.96%, respectively. The numerical calculation and experimental results show that the model can accurately calculate the strain along the plate thickness. This model can provide an important reference for the rolling process setup and the microstructure and properties prediction.

Real-time surface manipulation with $$C^{1}$$ continuity through simple and efficient physics-based deformations

We present a novel but simple physics-based method to interactively manipulate surface shapes of 3D models with $$ C^1 $$ C 1 continuity in real time. A fourth-order partial differential equation involving a sculpting force originating from elastic bending of thin plates is proposed to define physics-based deformations and achieve $$ C^1 $$ C 1 continuity at the boundary of deformation regions. In order to obtain real-time physics-based surface manipulation, we construct a mapping relationship between a deformation region in a 3D coordinate space and a unit circle on a 2D parametric plane, formulate corresponding $$ C^1 $$ C 1 continuous boundary conditions for the unit circle, and obtain a simple analytical solution to describe the physics-based deformation in the unit circle caused by a sculpting force. After that, the obtained physics-based deformation is mapped back to the 3D coordinate space, and added to the original surface to create a new surface shape with $$ C^1 $$ C 1 continuity at the boundary of the deformation region. We also develop an interactive user interface as a plug-in of the 3D modelling software package Maya to achieve real-time surface manipulation. The effectiveness, easiness, real-time performance, and better realism of our proposed method is demonstrated by testing surface deformations on several 3D models and comparing with other methods and ground-truth deformations.

MECHANICAL BEHAVIOR AND MICROSTRUCTURE EVOLUTION OF THE Ti-3Al-5Mo-4.5V ALLOY AT AN ELEVATED DEFORMATION TEMPERATURE

A high-performance titanium alloy requires a fine and homogenous microstructure. The rational deformation process parameters of the Ti-3Al-5Mo-4.5V (TC16) titanium alloy can contribute to achieving this important microstructure. Hot-compression experiments were performed at temperatures in the range 100–800 °C and at strain rates of 0.1 s–1 to 10.0 s–1. The effects of deformation temperatures and deformation rates on the mechanical behaviour and microstructure evolution were analysed and discussed. The softening mechanism of the Ti-3Al-5Mo-4.5V alloy at an elevated deformation temperature was revealed. Experimental results showed that 500 °C is the critical deformation temperature to distinguish the warm-deformation region of 100–400 °C and the hot-deformation region of 500–800 °C. The softening mechanism is dominated by -phase spheroidization in the temperature range 100–400 °C with a higher strain rate of 10.0 s–1. The softening mechanism is dominated by a local temperature rise in the temperature range 500–800 °C with a lower strain rate of 0.1 s–1.

Grain-to-Grain Interaction Effect in Polycrystalline Plain Low-Carbon Steel within Elastic Deformation Region

A grain is surrounded by grains with different crystal orientations in polycrystalline plain low-carbon steel. The grain is constrained by its adjacent grains in the tension process. The interaction of the grain with the adjacent grains was investigated within the elastic deformation region. The following results have been obtained: (1) the Young’s modulus of a grain without consideration of grain-to-grain interaction is denoted as the inherent Young’s modulus; when the inherent Young’s modulus of a grain is equal to the Young’s modulus of the bulk material, there is almost no interaction between the grain and its adjacent grains; when a grain has a great difference between its inherent Young’s modulus and the Young’s modulus of the bulk material, its grain-to-grain interactions increase significantly; (2) the grain-to-grain interaction is mainly caused by the difference in the inherent Young’s modulus between the grain and its adjacent grains; the misorientation angle between the grain and its adjacent grains has almost no effect on the grain-to-grain interaction.

Field evidence for fluid facilitated fracturing and Dissolution-Precipitaion creep explains observed off-fault tremor and continuous deformation: Field examples from the Alpine Fault, New Zealand

<div> <p>Geophysical observations show that the Alpine Fault in New Zealand is characterised by mid-crustal off-fault recurring tremor events and off-fault regions of continuous deformation. While geodesy indicates that deformation is distributed across the South Island, evidence from the rock record shows deformation accommodated in a region within several km from the fault. This zone is characterized by a 100-300 m wide mylonitised central fault zone and an approximately 8--10km, wide deformation region marked by the presence of Alpine foliation. Magnetotelluric surveys of the Southern Alps indicate a mid-crustal, high signal area coinciding with the location of the recurring tremors.  </p> </div><div> <p>While the mylonites and their associated mechanisms have been extensively studied in the field area, the wider off-fault deformation region has not had the same scrutiny. In the latter region, we observe frequent layer parallel, folded and crosscutting quartz veins. Quartz vein orientation and geometries are consistent with fracturing in the presence of fluid within an overall tectonic stress regime. The observed overprinting of older veins by younger vein generations, as well as their successive reorientations, indicate recurring fracturing within a continuously deforming region. Quantitative analysis of vein geometries including their width and displacement shows that vein formation may trigger the observed mid-crustal tremor signal. Microstructural signatures within the host rock are consistent with dissolution-precipitation creep as the main deformation mechanism in the host rock and pre-existing veins.  </p> </div><div> <p>In summary, according to field evidence both geophysically observed transient and continuous deformation take place in the presence of fluid and occur contemporaneously. This implies that strain accommodation in the host rock facilitated by dissolution-precipitation creep is insufficient; consequently, stress is build-up over time triggering intermittent fracturing.  </p> </div>

Design of a Kirigami Structure with a Large Uniform Deformation Region

We designed a kirigami structure with a particular shape at both ends to provide a large uniform deformation region when stretched. When a kirigami structure is stretched, non-deformation regions, where the regions’ cuts do not open, and non-uniform deformation regions, where the regions’ cuts are not uniformly deformed, are produced. The extent of the non-deformation and non-uniform deformation regions increases in proportion to the number of cut cycles in the width direction nw this reduces the percentage of the uniform deformation region. We propose a method that increases the uniform deformation region in a kirigami structure by deforming the shape of the ends from a rectangle to a trapezoid when stretched. The proposed kirigami structure has separation lines at both ends that separate cuts in the width direction, and the position of contacts at both ends are moved to the center. The proposed kirigami structure has a large uniform deformation region, even when nw is large, as evidenced by calculating the area of open cuts under stretching. The product of our study realizes a stretchable electro device with a large area, which maintains the position of evenly mounted functional elements when stretched.