Forming Al and Mg Alloy Sheet and Tube at Elevated Temperatures

2007 ◽  
Vol 344 ◽  
pp. 317-324 ◽  
Author(s):  
Taylan Altan ◽  
Serhat Kaya ◽  
Yingyot Aue-u-Ian
Keyword(s):  
Experimental Investigation ◽  
Magnesium Alloys ◽  
Elevated Temperatures ◽  
Tube Hydroforming ◽  
Alloy Sheet ◽  
Effect Of Temperature ◽  
Punch Velocity ◽  
Aluminum And Magnesium Alloys ◽  
Blank Size ◽  
Hydraulic Bulging

Experimental investigation on the formability limits of aluminum and magnesium alloys are conducted through hydraulic bulging and deep drawing. New tube hydroforming tooling was designed and the submerged tool concept is introduced. Tube hydroforming experiments were conducted with and without axial feed by using AA6061 tubes. The formability of Mg AZ31-O sheets are determined by hydraulic bulging using similar submerged tool. Finally the effect of temperature and initial blank size on the attainable highest punch velocity is investigated and round cups from Mg AZ31-O were successfully formed in a heated tool with punch speeds up to 300 mm/s.

An Experimental Study on Nonisothermal Deep Drawing Process Using Aluminum and Magnesium Alloys

2008 ◽  
Vol 130 (6) ◽  
Author(s):  
Serhat Kaya ◽  
Giovanni Spampinato ◽  
Taylan Altan
Keyword(s):  
Magnesium Alloys ◽  
Deep Drawing ◽  
Elevated Temperatures ◽  
Drawing Process ◽  
Deep Drawing Process ◽  
Punch Velocity ◽  
Forming Temperature ◽  
Tool Set ◽  
Aluminum And Magnesium Alloys ◽  
Blank Size

Weight reduction is one of the major goals in the automotive, appliance, and electronics industries. One way of achieving this goal is to use lightweight alloys such as aluminum and magnesium that have high strength to weight ratios. However, due to their limited formability at room temperature, forming needs to take place at elevated temperatures and mostly under nonisothermal conditions. In this study, nonisothermal deep drawing process using aluminum and magnesium alloys was investigated using a servo motor driven press and a heated tool set. Using the flexibility of the servo press kinematics, blanks were heated in the tool set prior to forming. Temperature-time measurements were made at various blank holder interface pressures in order to determine the required dwell time to heat the blank to the forming temperature. Several lubricants for elevated temperature forming were evaluated using the deep draw test, and a PTFE based film was found to be the best performing lubricant. Deep drawing tests were conducted to determine the process window (maximum punch velocity as functions of blank size and temperature) for Al 5754-O and Mg AZ31-O. Maximum punch velocities of 35 mm/s and 300 mm/s were obtained for the Al and Mg alloys, respectively. Comparisons for the Mg alloy sheets from two different suppliers were made and significant differences in formability were found. Experiments were conducted in order to understand the effect of constant and variable punch velocity and the temperature on the mechanics of deformation. Variable punch velocity is found to improve the thickness distribution of the formed part.

scholarly journals Cyclic Tension Test of AZ31 Magnesium Alloy at Elevated Temperature Realized in a Miniaturized Uniaxial Tensile Test Setup

2016 ◽  
Vol 854 ◽  
pp. 112-117
Author(s):  
Sebastian Suttner ◽  
Marion Merklein
Keyword(s):  
Elevated Temperature ◽  
Magnesium Alloy ◽  
Magnesium Alloys ◽  
Elevated Temperatures ◽  
Kinematic Hardening ◽  
Cyclic Behavior ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Hardening Behavior ◽  
Aluminum And Magnesium Alloys

The use of new materials, e.g. aluminum and magnesium alloys, in the automotive and aviation sector is becoming increasingly important to reach the global aim of reduced emissions. Especially magnesium alloys with their low density offer great potential for lightweight design. However, magnesium alloys are almost exclusively formable at elevated temperatures. Therefore, material characterization methods need to be developed for determining the mechanical properties at elevated temperatures. In particular, cyclic tests at elevated temperatures are required to identify the isotropic-kinematic hardening behavior, which is important for numerically modeling the springback behavior. In this contribution, a characterization method for determining the cyclic behavior of the magnesium alloy AZ31B at an elevated temperature of 200 °C is presented. The setup consists of a miniaturized tensile specimen and stabilization plates to prevent buckling under compressive load. The temperature in the relevant area is introduced with the help of conductive heating. Moreover, the complex kinematic model according to Chaboche and Rousselier is identified, to map the transient hardening behavior of AZ31B after load reversal, which cannot be modeled with a single Bauschinger coefficient.

Deep Drawing of AM31 Magnesium Alloys

2010 ◽  
Vol 654-656 ◽  
pp. 731-734
Author(s):  
Jae Hyung Cho ◽  
Li Li Chang ◽  
Suk Bong Kang
Keyword(s):  
Magnesium Alloys ◽  
Deep Drawing ◽  
Elevated Temperatures ◽  
Drawing Ratio ◽  
Ingot Casting ◽  
Roll Casting ◽  
Different Types ◽  
Conventional Ingot ◽  
Blank Size ◽  
Twin Roll

Texture and microstructure evolutions during deep drawing of AM31 magnesium alloys were investigated at various temperatures and deformation rates. Two different types of sheets were fabricated by twin roll strip and conventional ingot casting. They were warm-rolled down to 0.6mm and then fully-annealed for deep drawing. Drawing temperatures were 200oC to 350oC and punch rates, 30mm/min, 40mm/min, and 50mm/min. The blank size and punch diameter were 74mm and 37mm, respectively, and thus overall maximum drawing ratio was 2.0. Processing maps for deep drawing of both sheets at elevated temperatures were suggested. Initial textures showed typical basal fibers with an axisymmetric arrangement. Sheets made by ingot casting had larger grain size than those by twin roll casting. The basal fibers were evolved into other orientations during deep drawing, which contained both compression along the circumferential direction in the flange and tension along the drawing direction in the cup wall. Most evident reorientations were found in the flange. With deformation, finer grains increased. Necking and cup-failure were usually expected in the lower wall near the bottom.

Effect of Temperature, Velocity Gradient and I.V. Heparin on in Vitro Blood Coagulation and Platelet Aggregation

1967 ◽  
Vol 17 (01/02) ◽  
pp. 112-119 ◽  
Author(s):  
L Dintenfass ◽  
M. C Rozenberg
Keyword(s):  
Blood Coagulation ◽  
Velocity Gradient ◽  
Elevated Temperatures ◽  
Morphological Changes ◽  
Effect Of Temperature ◽  
Clotting Time ◽  
Progressive Change ◽  
Aggregation Of Platelets ◽  
Microscopic Techniques

SummaryA study of blood coagulation was carried out by observing changes in the blood viscosity of blood coagulating in the cone-in-cone viscometer. The clots were investigated by microscopic techniques.Immediately after blood is obtained by venepuncture, viscosity of blood remains constant for a certain “latent” period. The duration of this period depends not only on the intrinsic properties of the blood sample, but also on temperature and rate of shear used during blood storage. An increase of temperature decreases the clotting time ; also, an increase in the rate of shear decreases the clotting time.It is confirmed that morphological changes take place in blood coagula as a function of the velocity gradient at which such coagulation takes place. There is a progressive change from the red clot to white thrombus as the rates of shear increase. Aggregation of platelets increases as the rate of shear increases.This pattern is maintained with changes of temperature, although aggregation of platelets appears to be increased at elevated temperatures.Intravenously added heparin affects the clotting time and the aggregation of platelets in in vitro coagulation.

Thermorheological Characterization of Elastoviscoplastic Carbopol Ultrez 20 Gel

2015 ◽  
Vol 137 (3) ◽  
Author(s):  
M. A. Hassan ◽  
Manabendra Pathak ◽  
Mohd. Kaleem Khan
Keyword(s):  
Experimental Investigation ◽  
Yield Stress ◽  
Elastic Properties ◽  
Viscous Dissipation ◽  
Power Law ◽  
Effect Of Temperature ◽  
Rheological Parameters ◽  
Frequency Range ◽  
Power Law Index

The temperature and concentration play an important role on rheological parameters of the gel. In this work, an experimental investigation of thermorheological properties of aqueous gel Carbopol Ultrez 20 for various concentrations and temperatures has been presented. Both controlled stress ramps and controlled stress oscillatory sweeps were performed for obtaining the rheological data to find out the effect of temperature and concentration. The hysteresis or thixotropic seemed to have negligible effect. Yield stress, consistency factor, and power law index were found to vary with temperature as well as concentration. With gel concentration, the elastic effect was found to increase whereas viscous dissipation effect was found to decrease. Further, the change in elastic properties was insignificant with temperature in higher frequency range of oscillatory stress sweeps.

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