Superplastic forming characteristics of fine-grained 5083 aluminum

1995 ◽  
Vol 4 (5) ◽  
pp. 543-550 ◽  
Author(s):  
R. Verma ◽  
P. A. Friedman ◽  
A. K. Ghosh ◽  
C. Kim ◽  
S. Kim
Keyword(s):  
Superplastic Forming ◽  
Fine Grained ◽  
Forming Characteristics

Superplastic Forming Characteristics of a Fine-Grained Cu-Based Shape Memory Alloy

2012 ◽  
Vol 579 ◽  
pp. 22-31
Author(s):  
Chin Chuan Hsu
Keyword(s):  
Superplastic Forming ◽  
Rate Of Change ◽  
Dome Height ◽  
Base Line ◽  
Fine Grained ◽  
Forming Temperature ◽  
Forming Characteristics ◽  
Temperature And Pressure ◽  
Increasing Temperature ◽  
Free Bulging

The influences of temperature and pressure on the blow forming of CuZnAlZr sheet was investigated under free bulging conditions using argon gas. The effects evaluated were the dome height, measured at the dome apex; the specific thickness, the ratio of the actual thickness to the initial thickness; and the thinning factor, the ratio of the actual thickness to the average thickness. The results show that the dome height and the rate of change of dome height with respect to time, dh/dt, increase with increasing temperature and/or pressure. The specific thickness decreases with increasing fractional height (the ratio of the height of a given point above the base line to the height of the apex), and the specific thickness at the apex decreases with increasing temperature and/or pressure as well. The thinning factor decreases with increasing fractional height. Furthermore, this decrease becomes more significant with an increase in either the forming temperature or pressure. The thinning factor at the apex, as a function of the height to base ratio for all conditions falls into the region between m=0.3 and m=0.75 curves.

Effect of Different Proportion of Coarse and Fine Grain Microstructure on Superplastic Forming Characteristics

2016 ◽  
Vol 838-839 ◽  
pp. 528-533
Author(s):  
Vivek Pancholi ◽  
K. Rohit ◽  
A. Raja
Keyword(s):  
Superplastic Forming ◽  
Stir Zone ◽  
Thickness Variation ◽  
Friction Stir ◽  
Fine Grained ◽  
Fine Grain ◽  
Forming Characteristics ◽  
Inhomogeneous Microstructure ◽  
Bulge Height ◽  
The Ideal

The study was carried out to understand the effect of inhomogeneous microstructure on thickness variation in superplastically formed bulge. Friction stir processing was performed at rotational and traverse speeds of 720rpm and 155mm/min respectively on a 6mm sheet maintaining 50% overlap on the retreating side. Different probe dimensions were selected to obtain different proportions of fine grained stir zone in thickness direction. The proportions of the fine grained stir zone were 25%, 50%, 72% and, 100%. The sheets containing inhomogeneous microstructure were subjected to superplastic bulge forming under constant gas pressure up to a bulge height of 23.5mm. The sheet which was processed with 72% fine grains showed lower thickness variation from edge to apex and the bulge shape in this condition was close to the ideal spherical profile.

Superplastic Behavior and Microstructure of Titanium (Ti-6Al-4V) Friction Stir Welds Made under a Variety of Processing Conditions

2010 ◽  
Vol 433 ◽  
pp. 169-176 ◽  
Author(s):  
Paul Edwards ◽  
Mamidala Ramulu ◽  
Daniel G. Sanders
Keyword(s):  
Friction Stir Welding ◽  
Base Material ◽  
Superplastic Forming ◽  
Spindle Speed ◽  
Processing Conditions ◽  
Superplastic Behavior ◽  
Friction Stir ◽  
Fine Grained ◽  
Weld Parameters

Friction Stir Welding of Ti-6Al-4V was performed on 5 mm thickness plate in order to assess the affect of welding conditions on the resulting microstructure and superplastic forming behavior of the joints. A variety of welding conditions were tested and all welds were subsequently Superplastically formed. It was found that the weld parameters do influence the microstructure and degree of superplastic performance of the joints. Spindle speed was found to have the most dominant affect on the resulting microstructure and superplastic forming behavior. Low spindle speed welds lead to fine grained microstructures and highly superplastic welds, relative to the base material, while high spindle speed welds larger grained microstructures and less superplastic welds.

High-Temperature Deformation of Magnesium ElektronTM 43

2012 ◽  
Vol 735 ◽  
pp. 93-100
Author(s):  
Alexander J. Carpenter ◽  
Anthony J. Barnes ◽  
Eric M. Taleff
Keyword(s):  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Rate Sensitivity ◽  
Superplastic Forming ◽  
Solute Drag ◽  
Grain Boundary Sliding ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Fine Grained ◽  
Boundary Sliding

Complex sheet metal components can be formed from lightweight aluminum and magnesium sheet alloys using superplastic forming technologies. Superplastic forming typically takes advantage of the high strain-rate sensitivity characteristic of grain-boundary-sliding (GBS) creep to obtain significant ductility at high temperatures. However, GBS creep requires fine-grained materials, which can be expensive and difficult to manufacture. An alternative is provided by materials that exhibit solute-drag (SD) creep, a mechanism that also produces elevated values of strain-rate sensitivity. SD creep typically operates at lower temperatures and faster strain rates than does GBS creep. Unlike GBS creep, solute-drag creep does not require a fine, stable grain size. Previous work by Boissière et al. suggested that the Mg-Y-Nd alloy, essentially WE43, deforms by SD creep at temperatures near 400°C. The present investigation examines both tensile and biaxial deformation behavior of ElektronTM 43 sheet, which has a composition similar to WE43, at temperatures ranging from 400 to 500°C. Data are presented that provide additional evidence for SD creep in Elektron 43 and demonstrate the remarkable degree of biaxial strain possible under this regime (>1000%). These results indicate an excellent potential for producing complex 3-D parts, via superplastic forming, using this particular heat-treatable Mg alloy.

The Microstructure and Superplastic Behavior of Clean Mechanically Alloyed Titanium–Titanium Boride Alloys

1999 ◽  
Vol 601 ◽  
Author(s):  
A.P. Brown ◽  
R Brydson ◽  
C. Hammond ◽  
A. Wisbey ◽  
T.M.T. Godfrey
Keyword(s):  
Sheet Material ◽  
Hot Isostatic Pressing ◽  
Superplastic Forming ◽  
Titanium Boride ◽  
Production Cycle ◽  
Microstructural Development ◽  
Mechanically Alloyed ◽  
Boron Powder ◽  
Fine Grained ◽  
The Matrix

AbstractThe superplastic forming (SPF) of titanium alloys is an established technology. A reduction in grain size from that of the typical sheet materials would lead to enhanced SPF properties and hence a reduction in production cycle times. This study describes the microstructural development and superplastic behaviour of fine-grained Ti-6%Al-4%V alloys. Ball-milling Ti-6%Al-4%V powder produces a nanocrystalline material; however on consolidation by hot isostatic pressing rapid grain growth occurs. Addition of boron powder during milling leads to boride precipitates in the matrix of the consolidated alloy. The precipitates are dispersed inhomogeneously, resulting in localized grain refinement. Superplastic testing revealed cavitation formation but in comparison to conventional sheet material, large elongations were achieved at relatively high strain rates.

Superplastic Forming Characteristics and Microstructural Development of an Aluminium Lithium Alloy (8090)

1990 ◽  
Vol 196 ◽  
Author(s):  
G. J. Mahon ◽  
R. Keyte ◽  
N. C. Parson ◽  
R. A. Ricks
Keyword(s):  
Test Temperature ◽  
Superplastic Forming ◽  
Microstructural Development ◽  
Temperature Range ◽  
Lithium Alloy ◽  
Steady Decrease ◽  
Rapid Fall ◽  
Stress Changes ◽  
Rate Testing ◽  
Forming Characteristics

ABSTRACTSuperplastic testing of the aluminium-lithium alloy 8090 has been performed in the temperature range 485°C to 550°C. Up to 530°C, raising the test temperature has the effect of increasing the m-value and decreasing the flow stress. Changes in superplastic forming characteristics and microstructure have been followed during straining using a variety of techniques. Jump-strain rate testing reveals that in the optimum temperature range (515°C to 525°C).there is a steady decrease in m-value. Cavitation also occurs, but can be suppressed effectively by applying a hydrostatic pressure during testing. Raising the test temperature above this optimum range to 550°C produces a significant decrease in the m-value and a more rapid fall-off with strain. These observations are explained in terms of recrystallisation and grain growth, and the effectiveness of precipitates in pinning grain boundaries at the various temperatures.

Annealing Response of Al-0.22Sc-0.13Zr Alloy Processed by Accumulative Roll Bonding

2008 ◽  
Vol 584-586 ◽  
pp. 899-904 ◽  
Author(s):  
Petr Homola ◽  
Margarita Slámová ◽  
Vladivoj Očenášek ◽  
J. Uhlíř ◽  
Miroslav Cieslar
Keyword(s):  
Thermal Stability ◽  
Plastic Deformation ◽  
Accumulative Roll Bonding ◽  
Superplastic Forming ◽  
Aged Specimen ◽  
Roll Bonding ◽  
Fine Grained ◽  
Peak Aged ◽  
Pre Treatment ◽  
Thermal Stability Of

Ultra-fine grained (UFG) materials can be produced by several techniques involving severe plastic deformation (SPD). Accumulative Roll Bonding (ARB) is one of the SPD methods that enable the production of large amounts of UFG sheets. UFG sheets were prepared by up to six cycles of ARB at ambient temperature from an Al-0.22Sc-0.13Zr alloy in two states: a non-agehardened and a peak-aged. The effect of Al3(Sc1-xZrx) precipitates on the thermal stability of the UFG structures produced by ARB was investigated by isochronal annealing at temperatures between 200 and 550 °C. Additionally, the non-age-hardened ARB material was peak-aged prior to annealing and annealed together with both as-ARB-processed materials. The changes of microstructure and hardness due to annealing were studied. Annealing at 300 °C induces an additional strengthening in both non-pre-aged ARB materials that may be ascribed to precipitation and growth of coherent Al3(Sc1-xZrx) particles. This result suggests that the hardness decrease introduced by ARB in the peak-aged specimen is due to dissolution of precipitates during deformation. The annealing response of the materials above 300 °C does not depend on their thermal pre-treatment. However, the finely dispersed Al3(Sc1-xZrx) precipitates stabilise the refined deformed microstructure suitable for superplastic forming up to relatively high temperatures.

Crystallization of Cordierite Glass Ceramics for Joining SiC: Must Phase Separation Via Spinodal Decomposition Precede Nucleation?

1997 ◽  
Vol 3 (S2) ◽  
pp. 631-632
Author(s):  
Warren J. MoberlyChan ◽  
T. J. Perham ◽  
L. C. DeJonghe
Keyword(s):  
Phase Separation ◽  
Coefficient Of Thermal Expansion ◽  
Glass Ceramics ◽  
Superplastic Forming ◽  
Secondary Phases ◽  
Flexible Control ◽  
Fine Grained ◽  
Cordierite Glass ◽  
Lower Temperature ◽  
Crystallization Of Glass

The crystallization of glass ceramics provides processing advantages for difficult shapes. Machining and sintering are limited to produce complex parts; similarly (superplastic) forming is limited to special ceramics. In theory, however, a liquid (or glass) may be simply poured into any shape, and then crystallized (or partially crystallized) to provide a strong, tough ceramic. In this work, a thin layer of glass ceramic, cordierite (2MgO.2Al2O3.5SiO2), joins SiC [1]. Tailoring secondary phases and percent crystallization provide flexible control of the coefficient of thermal expansion to minimize strain mismatches between the joint components.Three processing steps are involved in crystallization of glass ceramics: first a fast quench produces the initial glass; the second step is a lower temperature “nucleation” anneal, where phase separation and/or precursors and/or the final structure is nucleated and ideally as a fine dispersion; the third step is the higher temperature “crystallization” anneal, where renucleation and/or growth develops a homogeneous (ideally fine grained) final crystalline product [2, 3].

Texture of Al-Cu Alloys Deformed by ECAP

2005 ◽  
Vol 495-497 ◽  
pp. 851-856 ◽  
Author(s):  
Jan Kuśnierz ◽  
Marie Helene Mathon ◽  
Thierry Baudin ◽  
Zdzislaw Jasieński ◽  
Richard Penelle
Keyword(s):  
Grain Size ◽  
Aluminium Alloys ◽  
Superplastic Forming ◽  
Orientation Distribution ◽  
Coarse Grained ◽  
Fine Grained ◽  
Angular Pressing ◽  
Cu Alloys ◽  
Super Plastic ◽  
Short Time

Materials of ultra-fine grained microstructure (sub-micrometer grain size) exhibit large strength, hardness and ductility and also the increased toughness in comparison with conventional coarse-grained ones. In these materials also the super-plastic flow at lower temperatures is observed. This behaviour may be interesting when aluminium alloys like AlCuZr, used in superplastic forming, are considered. In the paper, the methods of preparing such materials by equal-channel angular pressing (ECAP) is proposed and the texture analysis, based on neutron diffraction pole figure measurements and calculated orientation distribution function of two alloys AlCu4SiMn and AlCu5AgMgZr is discussed. The influence of short time recrystallization is discussed in relation with TEM and SEM observations.

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