Formability of LZ Magnesium Alloy Sheets
Date Issued
2006
Date
2006
Author(s)
Liao, Chih-Chieh
DOI
zh-TW
Abstract
Due to its lightweight and high specific strength, magnesium alloys have been widely used for structural components. However, because of the hexagonal closed-packed (HCP) crystal structures, magnesium alloys show low ductility at room temperature, and require thermal activation to increase their formability. It is well known that ductility of magnesium alloys can be improved with addition of lithium which develops the formation of body centered-cubic (BCC) crystal structures. The BCC crystal structure gives rise to high formability at room temperature.
The formability of different magnesium-lithium alloy sheets, such as LZ61、LZ91 and LZ101, was investigated by conducting various experiments in the present study. Tensile tests and forming limit tests were first conducted to investigate the mechanical behavior and formability of magnesium-lithium alloys with various lithium content. CCV tests and cup drawing tests were also performed to examine the stamping formability at room temperature. The experimental results reveal that the formability is much improved with higher Li content. Since the friction coefficient is one of important parameters in a stamping process, friction tests were preformed with the use of different lubricants and without lubrication. The friction coefficients obtained from the friction tests suggest appropriate lubricants to be used in the stamping of magnesium-lithium alloy sheets. In addition, V-bend tests were performed
to examine the springback property and minimum bending radius of magnesium-lithium alloy sheets at room temperature. Except for structural components, magnesium-lithium alloys can also be used for loudspeaker diaphragms because of its higher internal damping loss. Damping tests were performed to examine the damping coefficient of magnesium-lithium alloy sheets and the results were compared with those obtained for aluminum alloys. The experimental results obtained in the present study provide the fundamentals for the stamping die design of forming magnesium-lithium alloy sheets.
Subjects
鎂鋰合金
LZ61
LZ91
LZ101
沖壓成形性
CCV
成形極限
阻尼係數
magnesium-lithium alloys
stamping formability
forming limit
damping ratio
Type
thesis
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