Numerical and Experimental Investigation on the Hybrid Superplastic Forming of the Conical Mg Alloy Component

2018 ◽  
Vol 385 ◽  
pp. 391-396
Author(s):  
Mei Ling Guo ◽  
Ming Jen Tan ◽  
Xu Song ◽  
Beng Wah Chua
Keyword(s):  
Electron Backscatter Diffraction ◽  
Thickness Distribution ◽  
Superplastic Forming ◽  
Test Results ◽  
Forming Process ◽  
Hyperbolic Sine ◽  
Coarse Grains ◽  
Hot Drawing ◽  
Material Forming ◽  
Backscatter Diffraction

Hybrid superplastic forming (SPF) is a novel sheet metal forming technique that combines hot drawing with gas forming process. Compared with the conventional SPF process, the thickness distribution of AZ31B part formed by this hybrid SPF method has been significantly improved. Additionally, the microstructure evolution of AZ31 was examined by electron backscatter diffraction (EBSD). Many subgrains with low misorientation angle were observed in the coarse grains during SPF. Based on the tensile test results, parameters of hyperbolic sine creep law model was determined at 400 oC. The hybrid SPF behavior of non-superplastic grade AZ31B was predicted by ABAQUS using this material forming model. The FEM results of thickness distribution, thinning characteristics and forming height were compared with the experimental results and have shown reasonable agreement with each other.

Hybrid Superplastic Forming of Non-Superplastic AZ31 Mg Alloy

2016 ◽  
Vol 838-839 ◽  
pp. 534-539
Author(s):  
Mei Ling Guo ◽  
Ming Jen Tan ◽  
Xu Song ◽  
Beng Wah Chua
Keyword(s):  
Magnesium Alloy ◽  
Electron Backscatter Diffraction ◽  
Thickness Distribution ◽  
Superplastic Forming ◽  
Forming Process ◽  
Az31 Mg Alloy ◽  
Electron Backscatter ◽  
Hot Drawing ◽  
Backscatter Diffraction ◽  
First Contact

In this work, magnesium alloy sheets of non-superplastic grade AZ31 were successfully formed by a proposed hybrid superplastic forming at 400 °C within 22 min. During the forming process, hot drawing first formed the part partially from the starting metal sheet within a few seconds, and then followed by a designed gas forming process to achieve the desired conical shape by high gas pressure at a targeted strain rate. The maximum thinning of 59 % was found to occur at the first contact area between the material and the punch. The thickness distribution and superplastic deformation behavior during the hybrid superplastic forming were investigated. In addition, the microstructure evolutions of AZ31 at different forming stages were examined by electron backscatter diffraction. Superplastic forming capability of the non-superplastic grade magnesium alloy was achieved. Furthermore, the part formed by this superplastic-like forming was done faster and attained a more even material distribution than conventional superplastic forming.

Research on Quick Superplastic Forming Technology of Industrial Aluminum Alloys for Rail Traffic

2018 ◽  
Vol 385 ◽  
pp. 468-473 ◽  
Author(s):  
Guo Feng Wang ◽  
Hui Hui Jia ◽  
Yi Bin Gu ◽  
Qing Liu
Keyword(s):  
Aluminum Alloy ◽  
High Speed ◽  
Thickness Distribution ◽  
New Technology ◽  
Side Wall ◽  
Superplastic Forming ◽  
Forming Process ◽  
Forming Technology ◽  
Hot Drawing ◽  
Industrial Aluminum

Quick superplastic forming is a new technology, which combines hot drawing preforming and superplastic forming. It makes full use of the high speed of hot drawing and good formability of superplasticity. For aluminum alloy complex components, the difficulties of stamping and low speed of superplasticity be perfect solved. In this work, the best forming process of side wall outer panel of metro vehicle was determined by forming experiment using quick superplastic forming technology. The high-speed rail edge skin with a very small fillet shape (R≤4 mm) and the large-size subway door frame part (h≈80 mm) formed by straight wall deep drawing were manufactured, using industrial aluminum alloy sheet with thickness of 4 mm. Meanwhile, the formed parts show the advantages of high dimensional accuracy and uniform wall thickness distribution, and the mechanical properties of formed parts can completely meet the requirements as well, which demonstrates the desirable efficiency, low cost and feasibility of this new technology.

scholarly journals Optimization of Superplastic Forming Process of AA7075 Alloy for the Best Wall Thickness Distribution

2021 ◽  
Vol 6 (4) ◽  
pp. 251-261
Author(s):  
Manh Tien Nguyen ◽  
Truong An Nguyen ◽  
Duc Hoan Tran ◽  
Van Thao Le
Keyword(s):  
Wall Thickness ◽  
Deformation Temperature ◽  
Numerical Optimization ◽  
Thickness Distribution ◽  
Superplastic Forming ◽  
Forming Process ◽  
Wall Thickness Distribution ◽  
Surface Method ◽  
Series Of Experiments ◽  
The Relationship

This work aims to optimize the process parameters for improving the wall thickness distribution of the sheet superplastic forming process of AA7075 alloy. The considered factors include forming pressure p (MPa), deformation temperature T (°C), and forming time t (minutes), while the responses are the thinning degree of the wall thickness ε (%) and the relative height of the product h*. First, a series of experiments are conducted in conjunction with response surface method (RSM) to render the relationship between inputs and outputs. Subsequently, an analysis of variance (ANOVA) is conducted to verify the response significance and parameter effects. Finally, a numerical optimization algorithm is used to determine the best forming conditions. The results indicate that the thinning degree of 13.121% is achieved at the forming pressure of 0.7 MPa, the deformation temperature of 500°C, and the forming time of 31 minutes.

An Study of Nanoscale Mechanical Twins in GH4169 Alloy by Laser Shot Peening Processing

2021 ◽  
Vol 1027 ◽  
pp. 155-162
Author(s):  
Qiang Wang
Keyword(s):  
Shot Peening ◽  
Electron Backscatter Diffraction ◽  
Laser Shot ◽  
Near Surface ◽  
Refined Grains ◽  
Transmission Electron ◽  
Coarse Grains ◽  
Mechanical Twins ◽  
Backscatter Diffraction ◽  
Gh4169 Alloy

In order to study the mechanism of the fatigue strengthening using laser shot peening in GH4169 alloy, micro-structural and nanoscale mechanical twins (MT) at different depth below the top surface subjected to laser shot peening processing (LSP) were investigated by means of electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM) observations. In terms of the experimental observations and analyses, the formation of refined grains and nanoscale MT mechanism at the near surface of GH4169 alloy as a function of LSP treament can be summarized as follows: (i) two direction low density of MTs divide the initial coarse grains into submicron rhombic blocks; (ii) high density of MTs aligned in two directions subdivide the submicron rhombic blocks into nanoscale rhombic MT blocks; (iii) the third direction MT further refine the nanoscale rhombic MT blocks into nanoscale triangular MT blocks; (iv) some of subdivided blocks evolve into refined grains. An ultra-high strain rate induced by ultra-short laser pulse plays a key role in the formation of refined grains and nanoscale MT during plastic deformation of GH4169 alloy subjected to LSP treatment.

Numerical Simulation of Bulging Process of Aluminum Alloy Sheet

2013 ◽  
Vol 327 ◽  
pp. 112-116 ◽  
Author(s):  
Mao Ting Li ◽  
Yong Zhang ◽  
Chui You Kong
Keyword(s):  
Aluminum Alloy ◽  
Material Flow ◽  
Thickness Distribution ◽  
Superplastic Forming ◽  
Alloy Sheet ◽  
Pressure Loading ◽  
Forming Process ◽  
Element Analysis ◽  
Danger Zone ◽  
Linear Finite Element

Basing on software MSC. Marc of non-linear finite element analysis, the article has studied the material flow in the process of aluminum alloy superplastic gas bulging forming. By analyzing of the thickness distribution of the molding member it confirm the danger zone in the forming process. By analyzing of pressure loading curve influence on forming part. Because the aluminum alloy is widely used in the industrial departments, it is supposed to improve the ability of forming ability of aluminum alloy by researching the superplastic forming.

Crystallography of Natural and Synthetic Gold Alloy Microstructures

2013 ◽  
Vol 753 ◽  
pp. 477-480 ◽  
Author(s):  
Angela Halfpenny ◽  
Robert Hough ◽  
Michael Nugus
Keyword(s):  
Lattice Distortion ◽  
Electron Backscatter Diffraction ◽  
Gold Foil ◽  
Gold Deposition ◽  
Synthetic Sample ◽  
Coarse Grains ◽  
Formation Conditions ◽  
Backscatter Diffraction ◽  
Gold Microstructures ◽  
Natural And Synthetic

To improve our understanding of the mechanisms of gold deposition, a comparison was made of the microstructures of a natural gold sample with a synthetic gold foil of similar alloy composition (approximately Au 90%, Ag 10%). The aim was to identify any similarities between the samples that could help increase our knowledge of how the natural gold microstructures formed and were modified post-mineralisation. The samples were analysed using electron backscatter diffraction to map their microstructure, with the synthetic gold foil then heated to and mapped at 400°C, 500°C, 600°C and 700°C. Both the natural and synthetic sample exhibited a dominance of ∑3 twin boundaries, but these were much less abundant in the synthetic sample prior to heating. The natural sample is dominated by coarse grains exhibiting lattice distortion and low angle grain boundaries, which more closely resemble the synthetic gold foil microstructure after recrystallisation has taken place, than the initial microstructure, implying that the grains have had time to grow. Performing experiments such as these allows direct comparison of gold microstructures where the formation conditions are known and the controlling mechanisms can be determined. This will improve our understanding of the important mechanisms behind gold deposition.

The Occurrence of a Peripheral Coarse Grain Zone (PCGZ) in Extruded Bars of AA 7108

2021 ◽  
Vol 1016 ◽  
pp. 1141-1146
Author(s):  
Saul Hissaci de Souza ◽  
Ronald Lesley Plaut ◽  
Nelson Batista de Lima ◽  
Rene Ramos de Oliveira ◽  
Angelo Fernando Padilha
Keyword(s):  
Electron Backscatter Diffraction ◽  
Microstructural Analysis ◽  
Polarized Light ◽  
Coarse Grain ◽  
X Ray Diffraction ◽  
Rectangular Section ◽  
X Ray ◽  
Analysis Techniques ◽  
Coarse Grains ◽  
Backscatter Diffraction

Industrial-scale extruded profiles of AA 7108 with a rectangular section (25.60 mm x 15.95 mm) were used in this investigation. Some complementary microstructural analysis techniques, such as polarized light microscopy, EBSD (Electron Backscatter Diffraction) and X-ray diffraction were used to characterize the microstructure, focusing on the PCG zone. It was observed that the extruded profiles presented a totally recrystallized microstructure and a 300 μm layer of peripheral coarse grains. Additionally, the results showed that the PCGZ predominant grain orientation {311} <110> differs from the texture below the PCGZ (Goss and Cube components).

scholarly journals The microstructure of meteoric ice from Vostok, Antarctica

2007 ◽  
Vol 53 (180) ◽  
pp. 41-62 ◽  
Author(s):  
Rachel Obbard ◽  
Ian Baker
Keyword(s):  
Electron Backscatter Diffraction ◽  
Impurity Content ◽  
Microstructural Development ◽  
Glacial Ice ◽  
Fine Grained ◽  
Grain Boundary Mobility ◽  
Coarse Grains ◽  
Vostok Station ◽  
Glacial Periods ◽  
Backscatter Diffraction

AbstractThe 3623 m long, 5G core collected at Vostok station, Antarctica, contains alternating layers of meteoric ice with two distinctly different microstructures. In this paper, we present the microstructure and impurity content of a number of specimens ranging in depth from 97 to 3416 m, describe in detail the characteristics of the different layers and propose a mechanism for their microstructural development. Digital image analysis, ion chromatography, scanning electron microscopy and energy dispersive X-ray spectroscopy were used to measure texture and the location and type of impurities; electron backscatter diffraction was used to determine crystal orientation. The ice associated with interglacial periods is characterized by relatively coarse grains and a strong preferred orientation of the c axes in a plane encompassing the coring direction, producing a vertical-girdle fabric. In contrast, ice from glacial periods is characterized by a much smaller grain size and a strong singlemaximum fabric, where the c axes are clustered around the vertical. Calcium is uniquely present in the grain boundaries of the fine-grained glacial layers, and its effect on grain-boundary mobility and the misorientation dependence of mobility can explain the development of the discontinuous microstructure seen in glacial ice at Vostok station.

Effect of Local Texture on the Orange Peel Defect in St14 Steel Sheet

2005 ◽  
Vol 495-497 ◽  
pp. 167-172
Author(s):  
Sheng Quan Cao ◽  
Jin Xu Zhang ◽  
Jian Sheng Wu ◽  
Jia Guang Chen
Keyword(s):  
Slip System ◽  
Steel Sheet ◽  
Electron Backscatter Diffraction ◽  
Orange Peel ◽  
Phase Zone ◽  
Coarse Grains ◽  
Schmid Factor ◽  
Ebsd Technique ◽  
Backscatter Diffraction ◽  
St14 Steel

In this paper, the ‘orange peel’ defect in the surface range of the st14 steel sheet has been investigated using the electron backscatter diffraction (EBSD) technique. It has been found that the ‘orange peel’ defect in the st14 steel sheet was resulted from the local coarse grains which were produced during hot-rolling due to the critical deformation in dual-phase zone; During deep drawing, the coarse grains with {100}<001> microtexture can slip on the {112}<111> slip system to form bulging and yields orange peel defects, while the coarse grains with {112}<110> orientation do not form the defect as the Schmid factor of {112}<111> slip system in it equals zero.

scholarly journals Effect of Incremental Shrinking Process on Mechanical Properties and Microstructure of Alloy through Electron Backscatter Diffraction Analysis

2021 ◽  
Vol 2083 (2) ◽  
pp. 022079
Author(s):  
Zhengwei Gu ◽  
Yusheng Li ◽  
Ziming Tang ◽  
Ge Yu
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
Electron Backscatter Diffraction ◽  
Mechanical Tests ◽  
Mechanical Anisotropy ◽  
Forming Process ◽  
Ebsd Data ◽  
Electron Backscatter ◽  
Shrinking Process ◽  
Backscatter Diffraction

Abstract In recent years, the incremental shrinking process has been widely used in the forming process of aluminum alloy components for the railway vehicles. The effect of the incremental shrinking process on the performance and microstructure of 6082-T6 aluminum alloy was investigated through mechanical tests and electron backscatter diffraction (EBSD) analysis. The tensile test specimens prepared in different rolling orientations (0˚,45˚and 90˚) along the original and deformed sheets exhibited the mechanical anisotropy. After the incremental shrinking process, the average microhardness, tensile strength, and yield strength of this alloy were respectively increased by nearly 8.78%,2.26%,2.72%, while the Elongation was decreased by almost 31.67%. By analyzing the EBSD data, the strength of the material is increased by the incremental shrinking process and its mechanical anisotropy is improved, whereas its plasticity is greatly deteriorated.

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