Superplastic Forming Limit and Instability of AZ31B Sheet

2011 ◽  
Vol 686 ◽  
pp. 343-347
Author(s):  
Mei Juan Song ◽  
Ling Yun Wang ◽  
Rao Chuan Liu
Keyword(s):  
Superplastic Deformation ◽  
Tensile Deformation ◽  
Forming Limit Diagram ◽  
Superplastic Forming ◽  
Alloy Sheet ◽  
Forming Limit ◽  
Local Necking ◽  
Bulging Test ◽  
First Time ◽  
Az31b Magnesium Alloy Sheet

The superplastic bulging test of AZ31B magnesium alloy sheet of 0.6mm thick was carried out on Alliance RT/50 tensile machine at 573K and 3.3×10-4S-1. It is found that either in tensile-compressive deformation or in bi-axis tensile deformation, the judgment criterion for local necking of superplastic deformation is dε2=0. The superplastic forming limit diagram(FLD) at 573K and 3.3×10-4S-1 was established for the first time.

Superplastic Forming Limit and Instability of AZ31B Sheet

2007 ◽  
Vol 546-549 ◽  
pp. 387-390
Author(s):  
Ling Yun Wang ◽  
Mei Juan Song ◽  
Rao Chuan Liu
Keyword(s):  
Magnesium Alloy ◽  
Superplastic Deformation ◽  
Tensile Deformation ◽  
Superplastic Forming ◽  
Alloy Sheet ◽  
Forming Limit ◽  
Local Necking ◽  
Bulging Test ◽  
First Time ◽  
Az31b Magnesium Alloy Sheet

The superplastic bulging test of AZ31B magnesium alloy sheet of 0.6mm thick was carried out on Alliance RT/50 tensile machine at 573K and 3.3×10 −4 −1 s . It is found that either in tensile-compressive deformation or in bi-axis tensile deformation, the judgment criterion for local necking of superplastic deformation is 0 2 dε = . The superplastic forming limit diagramFLDat 573K and 3.3×10 −4 −1 s was established for the first time.

The tensile deformation behavior of AZ31B magnesium alloy sheet under intermittent pulse current

2021 ◽  
pp. 095440622110242
Author(s):  
Ju Guo ◽  
Xiao-Lei Cui ◽  
Wen-Kai Zhao ◽  
Cheng-Zhong Chi ◽  
Xiao-Qing Cao ◽  
...  
Keyword(s):  
Magnesium Alloy ◽  
Deformation Behavior ◽  
Pulse Current ◽  
Tensile Deformation ◽  
Fracture Morphology ◽  
Alloy Sheet ◽  
Az31b Magnesium Alloy ◽  
Magnesium Alloy Sheet ◽  
Tensile Deformation Behavior ◽  
Az31b Magnesium Alloy Sheet

In this paper, to investigate the effect of loading method of pulse current on the tensile deformation behavior of AZ31B magnesium alloy sheet, the intermittent pulse current with short-time and high-frequency was introduced in uniaxial tensile tests and the influence of duty ratio and loading time of pulse current on the deformation behavior of AZ31B magnesium alloy sheet was discussed. The strain and temperature field distributions on the specimens were measured during the intermittent pulse electrically-assisted tension (IPEAT), and the microstructure and fracture morphology under different pulse current conditions were observed. Results shows appropriate pulse current parameters can effectively improve the elongation of AZ31B magnesium alloy sheet. The strain of the sample is closely related to temperature distribution. With the deformation of the sample, the temperature on the sample increases gradually and the temperature distribution is non-uniform along the tensile direction, resulting in an inhomogeneous strain distribution of the sample. In addition, grain growth and dynamic recrystallization were observed on the AZ31B magnesium alloy sheet in different degrees under intermittent pulse current. Fracture morphology analysis shows that the number of dimples and tearing edges increased on the fracture obtained under IPEAT. The microhardness analysis shows that when intermittent pulse current is applied in the tensile test, the hardness of the sheet may change. This research provides an effective idea for the forming process of magnesium alloy sheets, which can be used to form large size thin-walled sheet components, and can significantly improve the forming quality of the sheets.

Forming limit analysis of Mg-2Zn-1.2Al-0.2Ca-0.2RE alloy sheet using ductile fracture models

2019 ◽  
Vol 29 (8) ◽  
pp. 1181-1198 ◽  
Author(s):  
Fei-Fan Li ◽  
Gang Fang ◽  
Ling-Yun Qian
Keyword(s):  
Magnesium Alloy ◽  
Ductile Fracture ◽  
Stress Triaxiality ◽  
Forming Limit Diagram ◽  
Alloy Sheet ◽  
Image Correlation ◽  
Forming Limit ◽  
Correlation Technique ◽  
Forming Limits ◽  
Fracture Models

This work was aimed to experimentally and theoretically investigate the formability of a new magnesium alloy sheet at room temperature. The fracture forming limit diagram was predicted by MMC3 and DF2014 models, where the non-linear strain path effect was taken into account by means of damage accumulation law. In order to obtain the instantaneous values of the stress triaxiality and the Lode parameter during the deformation process, strains tracked by digital image correlation technique were transformed into stresses based on the constitutive equations. The fracture forming limit diagram predicted by the fracture models was compared with the forming limits obtained by ball punch deformation tests. The prediction errors were evaluated by the accumulative damage values, which verified the advantages of ductile fracture models in predicting the forming limits of the magnesium alloy sheets.

Left-Side of the Forming Limit Diagram (FLD) under Superimposed Double-Sided Pressure

2012 ◽  
Vol 472-475 ◽  
pp. 653-656
Author(s):  
Jian Guang Liu ◽  
Qing Yuan Meng
Keyword(s):  
Deformation Behavior ◽  
Strain Path ◽  
Damage Model ◽  
Forming Limit Diagram ◽  
Alloy Sheet ◽  
Forming Limit ◽  
Aluminum Alloy Sheet ◽  
The Finite Element Method ◽  
The Past ◽  
Deformation State

Over the past decades, many kinds of double-sided pressure forming processes have been proposed to improve the formability of lightweight materials which exhibit distinctly poor forming capability. In the present study, the effects of double-sided pressure on the deformation behavior of AA5052-O aluminum alloy sheet metal under tension-compression deformation state are studied numerically using the finite element method based on the Gurson damage model. It is demonstrated that superimposed double-sided pressure significantly increases the left-side of the forming limit diagram and the formability increase value is sensitive to the strain path.

A superplastic forming limit diagram concept for Ti-6Al-4V

2007 ◽  
Vol 221 (4) ◽  
pp. 251-264 ◽  
Author(s):  
M A Kröhn ◽  
S B Leen ◽  
T H Hyde
Keyword(s):  
Forming Limit Diagram ◽  
Superplastic Forming ◽  
Plastic Instability ◽  
Equivalent Strain ◽  
Forming Limit ◽  
Key Points ◽  
Microstructural Effects ◽  
Key Factor ◽  
Dynamic Grain Growth ◽  
The Hill

The current paper is concerned with the development of a simplified method for predicting failure due to plastic instability during the superplastic forming (SPF) of titanium alloys. The rationale is that a key factor in the process of reliable failure prediction is the incorporation of a mechanisms-based model, which includes microstructural effects, such as static and dynamic grain growth and associated hardening, and which is also independent of the forming strainrate. Existing methods for predicting plastic instability during conventional metal-forming are discussed along with previous attempts at predicting failure during SPF. It is shown that no easy-to-interpret method, such as the forming limit diagram (FLD) in conventional forming, exists for SPF. Consequently, an SPFLD concept in a major strain (ε1), minor strain (ε3), and equivalent strain-rate space (εeq) is presented on the basis of uniaxial SP ductilities across a range of strainrates along with the Hill-Swift instability criteria and using finite element-predicted ε1-ε3-εeq paths for key points on the forming blank to predict failure. The predicted results are validated against measured data for Ti-6Al-4V at different strain-rates.

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