Forming Limit Diagram of Magnesium Alloy ZK60 at Elevated Temperature

2011 ◽  
Vol 308-310 ◽  
pp. 2442-2445 ◽  
Author(s):  
Hong Wei Liu ◽  
Sheng Jie Yao ◽  
Wen Liang Liu ◽  
Zhao Duo Zhang
Keyword(s):  
Elevated Temperature ◽  
Magnesium Alloy ◽  
Grain Boundaries ◽  
Forming Limit Diagram ◽  
Strain Ratio ◽  
Instability Criterion ◽  
Forming Limit ◽  
Relationship Of ◽  
Zk60 Magnesium Alloy ◽  
The Relationship

The forming limit diagram of magnesium alloy ZK60 was developed with Hill’s instability criterion and M-K analysis. The relationship of forming limit with stain path, temperature and the thickness irregular coefficient were analyzed. The results show that the forming limit of ZK60 magnesium alloy increased little with the rising of strain ratio, but influenced greatly by the failure definition , and forming limit of is increased with the rising of temperature and thickness irregular coefficient, the most suitable value of f0 is 0.99, the fracture occur on the grain boundaries with significant cavities formation.

Forming Limit Diagram of Stainless Steel-Aluminum Alloy Clad

2010 ◽  
Vol 152-153 ◽  
pp. 541-544
Author(s):  
Hong Wei Liu ◽  
Peng Zhang
Keyword(s):  
Stainless Steel ◽  
Aluminum Alloy ◽  
Forming Limit Diagram ◽  
Strain Ratio ◽  
Thickness Ratio ◽  
Instability Criterion ◽  
Forming Limit ◽  
Interfacial Cracks ◽  
Positive Strain

The forming limit diagram of clad was developed with Hill’s instability criterion and M–K analysis at the positive strain ratio. The relationships of forming limit with stain path, thickness ratio and thickness irregular coefficient were analyzed. The results show that the forming limit of clad material is between those of its component materials, and increase with the rising of stainless steel thickness ratio and the thickness irregular coefficient. The most suitable value of f0 is 0.094 and the stainless steel aluminum clad break with local interfacial cracks.

Predicting forming limit diagrams for AZ31 magnesium alloy and 7050 aluminum alloy by numerical simulation

2020 ◽  
pp. 030932472098120
Author(s):  
Fengmei Xue ◽  
Yu Yan ◽  
Jincheng Kang
Keyword(s):  
Aluminum Alloy ◽  
Magnesium Alloy ◽  
Forming Limit Diagram ◽  
Az31 Magnesium Alloy ◽  
Instability Criterion ◽  
Forming Limit ◽  
Punch Force ◽  
Forming Limit Diagrams ◽  
Adjacent Element ◽  
7050 Aluminum Alloy

Forming limit diagram (FLD) is the most intuitive method to evaluate and analyze the forming performance of sheet metal, which is widely used in production. To examine the formability of AZ31 magnesium alloy and 7050 aluminum alloy, the simplified bulging models based on the Nakazima experiment are established by ABAQUS finite element (FE) software, and the maximum punch force criterion is adopted as the instability criterion. The forming limit diagrams of 7050 high-strength aluminum alloy at room temperature and AZ31 magnesium alloy at warm working conditions are obtained by extracting the in-plane strain of the adjacent element of the maximum strain element at the moment of instability. Compared with experimental observation shows that the Nakazima virtual model established in this paper can accurately predict FLD. In addition, the influences of lubrication conditions and virtual punching speeds on the bulging process of AZ31 and AA7050 sheet metals are also investigated. The results show that the better the lubrication environment, or the lower the punching speed, the better the formability of the sheet, and reducing the punching speed has a more significant improvement effect on the formability of AZ31 sheets.

Sheet Orientation Effects on the Formability Limits of the AZ31B Magnesium Alloy at SPF Conditions

2011 ◽  
Author(s):  
Fadi Abu-Farha ◽  
Brad Deeter
Keyword(s):  
Magnesium Alloy ◽  
Rolling Direction ◽  
Constant Strain Rate ◽  
Forming Limit Diagram ◽  
Superplastic Forming ◽  
Strain Ratio ◽  
Forming Limit ◽  
Az31b Magnesium Alloy ◽  
Novel Approach ◽  
Mechanical Stretching

The formability curves of the AZ31B magnesium alloy were constructed by following a novel approach that best resembles the conditions of actual Superplastic Forming (SPF) operations. Sheet samples were formed at 400 °C and a constant strain rate of 1×10−3 s−1, by free pneumatic bulging into a set of progressive elliptical die inserts. By doing so, the material in each of the formed domes was forced to undergo biaxial stretching at a distinct strain ratio, which is simply controlled by the geometry (aspect ratio) of the selected die insert. Material deformation was quantified using circle grid analysis (CGA), and the recorded planar strains were used to construct the forming limit diagram (FLD) of the material. The aforementioned was carried out with the sheet oriented either along or across the direction of major strains, in order to establish the relationship between the material’s rolling direction and the corresponding limiting strains. Great deviations between the two sets of formability curves are realised, hence a compound forming limit diagram is constructed as an improved way for characterising the material behaviour. The presented pneumatic stretching approach is shown to produce accurate friction-independent formability diagrams, with clear distinction between the safe and unsafe deformation zones, even though the developed diagrams are confined to the biaxial strain region (right side quadrant of an FLD). Moreover, the approach proves to be a viable means for providing formability maps under conditions where traditional mechanical stretching techniques (Nakajima and Marciniak tests) are limited.

scholarly journals ANALYSIS OF DEFORMATION PROCESSES OF MAGNESIUM ALLOY AT ELEVATED TEMPERATURES BY ORIENTATION MAPPING

2011 ◽  
Vol 23 (1) ◽  
pp. 53 ◽  
Author(s):  
Ping Yang ◽  
Li Meng ◽  
Yisong Hu ◽  
Zude Zhao ◽  
Xueping Ren
Keyword(s):  
Magnesium Alloy ◽  
Elevated Temperatures ◽  
Plastic Slip ◽  
Rotation Axes ◽  
Orientation Mapping ◽  
Back Scattering ◽  
Deformation Processes ◽  
Relationship Of ◽  
The Relationship

Orientation mapping based on electron back scattering diffraction technique was applied to reveal the distributions of disorientations and rotation axes of grains caused by plastic slip and twinning during channel die compression in magnesium alloy ZA31. In addition, the orientations of dynamically recrystallized grains and deformed grains were separated and compared with respect to their initial textures. The relationship of strain and {1012} twin amount was determined quantitatively by referring to twin orientations. The reasons leading to the observed phenomena are analyzed and discussed.

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.

1006 Effects of Temperature and Strain-Rate on Non-proportion Forming Limit Diagram for AZ31 Magnesium Alloy Sheets

2009 ◽  
Vol 2009.47 (0) ◽  
pp. 337-338
Author(s):  
Yosuke UEKAWA ◽  
Takashi KATAHIRA ◽  
Akiyoshi ODE ◽  
Testuo NAKA ◽  
Takeshi UEMORI ◽  
...  
Keyword(s):  
Magnesium Alloy ◽  
Strain Rate ◽  
Forming Limit Diagram ◽  
Az31 Magnesium Alloy ◽  
Forming Limit ◽  
Effects Of Temperature

Study of Bonding of Grain Boundaries in Steels Using EELS

2005 ◽  
Vol 475-479 ◽  
pp. 4063-4066
Author(s):  
X. Zhang ◽  
Lina Zhang ◽  
Jun Jie Qi ◽  
Yue Ma
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Intergranular Fracture ◽  
Fracture Mode ◽  
Fracture Property ◽  
Transgranular Fracture ◽  
The Difference ◽  
Relationship Of ◽  
The Relationship

A novel EELS technique was developed to study bonding of grain boundary in many kinds of steels. We measured the normalized intensities of Fe white lines and calculated the occupancies of 3d states of iron, and then analyzed the relationship of the occupancies of 3d states of iron and the fracture property of the steels. We found that if the grain boundary has a different occupancy of 3d state of iron from that of the bulk, the steel tends to have an intergranular fracture, whereas if the grain boundary has almost the same occupancy of 3d state as the bulk, the steel tends to have a transgranular fracture. Our result shows that the difference in the occupancy of 3d state between bulk and grain boundary can be used to study the fracture mode at grain boundary in steel.

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