Research on the Superplastic Forming of Copper Alloy Solid-Bearing Cages Used in Railway Vehicles

Author(s):  
Yong Shun Yang ◽  
Guo Qing Chen ◽  
F.X. Chen
2007 ◽  
Vol 551-552 ◽  
pp. 73-77 ◽  
Author(s):  
Yong Shun Yang ◽  
Guo Qing Chen ◽  
F.X. Chen

In this paper uniaxial tensile tests were carried out at temperature range of 650~810°C and initial strain rate range of 10-4~10-1s-1 to evaluate the superplasticity of as-casting aluminum-bronze QAl10-3-1.5 alloy. The superplastic forming technology (SPF) was adopted to produce solid-bearing cages made of aluminum-bronze QAl10-3-1.5 alloy. The results demonstrate that as-casting QAl10-3-1.5 copper alloy shows good superplasticity without prior-treatment. The maximum elongation of 545% is obtained at 790°C and initial strain rate of 1.0×10-2 s-1, while the maximum flow stress is only 12.4MPa. By using superplastic extrusion technology solid-bearing cages used in railway vehicles were obtained. As-extruded cages have good surface quality and the dimensional accuracy satisfies the design standards. Using this technology the production efficiency is greatly enhanced and the manufacturing cost is reduced, especially the expensive copper alloys are saved.


Author(s):  
J. I. Bennetch

In a recent study of the superplastic forming (SPF) behavior of certain Al-Li-X alloys, the relative misorientation between adjacent (sub)grains proved to be an important parameter. It is well established that the most accurate way to determine misorientation across boundaries is by Kikuchi line analysis. However, the SPF study required the characterization of a large number of (sub)grains in each sample to be statistically meaningful, a very time-consuming task even for comparatively rapid Kikuchi analytical techniques.In order to circumvent this problem, an alternate, even more rapid in-situ Kikuchi technique was devised, eliminating the need for the developing of negatives and any subsequent measurements on photographic plates. All that is required is a double tilt low backlash goniometer capable of tilting ± 45° in one axis and ± 30° in the other axis. The procedure is as follows. While viewing the microscope screen, one merely tilts the specimen until a standard recognizable reference Kikuchi pattern is centered, making sure, at the same time, that the focused electron beam remains on the (sub)grain in question.


Author(s):  
A. Cziráki ◽  
E. Ková-csetényi ◽  
T. Torma ◽  
T. Turmezey

It is known that the formation of cavities during superplastic deformation can be correlated with the development of stress concentrations at irregularities along grain boundaries such as particles, ledges and triple points. In commercial aluminium alloys Al-Fe-Si particles or other coarse constituents may play an important role in cavity formation.Cavity formation during superplastic deformation was studied by optical metallography and transmission scanning electron microscopic investigations on Al-Mg-Si and Al-Mg-Mn alloys. The structure of particles was characterized by selected area diffraction and X-ray micro analysis. The volume fraction of “voids” was determined on mechanically polished surface.It was found by electron microscopy that strongly deformed regions are formed during superplastic forming at grain boundaries and around coarse particles.According to electron diffraction measurements these areas consist of small micro crystallized regions. See Fig.l.Comparing the volume fraction and morphology of cavities found by optical microscopy a good correlation was established between that of micro crystalline regions.


2010 ◽  
Vol 54 (3-4) ◽  
pp. 107
Author(s):  
Barbara Horváth ◽  
Balázs Illés ◽  
Tadashi Shinohara ◽  
Gábor Harsányi
Keyword(s):  

1989 ◽  
Vol 16 (1) ◽  
pp. 81-84
Author(s):  
J. G. Scott
Keyword(s):  

Summary This copper alloy crucifix was found during excavation at Macewen's Castle in Argyll in 1968 and closely resembles others known to date from the 12th century; it may have been made in Belgium. The arms could have been bent back to aid concealment in the 17th or 18th centuries.


2018 ◽  
Vol 28 ◽  
pp. 419-456
Author(s):  
Martin Odler ◽  
Katharina Uhlir ◽  
Marie Jentsch ◽  
Martina Griesser ◽  
Regina Hölzl ◽  
...  
Keyword(s):  

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