A Study on the Tensile Properties and Ductile to Brittle Transition Characteristics of Mg-10Li-2Al-1Zn Extruded Alloy at Temperature Range of 248K~523K

碩士 === 國立成功大學 === 材料科學及工程學系碩博士班 === 97 === Magnesium alloys have many advantages such as low density, high specific strength, good mechanic damping properties and good radiation absorption of electromagnetic waves. They are commonly applied in traffic and electronic industries. Magnesium alloys with...

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Main Authors: Hao-En Hung, 洪浩恩
Other Authors: Li-hui Chen
Format: Others
Language:zh-TW
Published: 2009
Online Access:http://ndltd.ncl.edu.tw/handle/46593779263626706734
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spelling ndltd-TW-097NCKU51590422016-05-04T04:25:26Z http://ndltd.ncl.edu.tw/handle/46593779263626706734 A Study on the Tensile Properties and Ductile to Brittle Transition Characteristics of Mg-10Li-2Al-1Zn Extruded Alloy at Temperature Range of 248K~523K Mg-10Li-2Al-1Zn鎂合金擠型材於248K~523K之拉伸性質及延脆轉換特性探討 Hao-En Hung 洪浩恩 碩士 國立成功大學 材料科學及工程學系碩博士班 97 Magnesium alloys have many advantages such as low density, high specific strength, good mechanic damping properties and good radiation absorption of electromagnetic waves. They are commonly applied in traffic and electronic industries. Magnesium alloys with adding lithium element could make the density lower than the pure magnesium. This study focuses on tensile properties and ductile to brittle transition characteristics of the two-phase Mg-10Li-2Al-1Zn alloy, which is consist of HCP a-phase and BCC b-phase, at the temperature range of 248K ~ 523K (−25℃~250℃). Tensile testing results show that the ultimate tensile stress and the yield stress decreased with increasing temperatures. The uniform elongation has a maximum value at 50℃. The total elongation is significantly increased at the temperature range of RT~50℃, and it further increases to 55% at 100℃. The ductile to brittle transition behavior is occurred at the temperature range of RT~50℃. Fracture sub-surfaces reveal that initial cracks occurred within a-phase and a/b-phase interfaces. At low temperatures, failures are resulted from cracks propagation and inter-connection rapidly. When the temperature raising upon 50℃, cracks grow into pores by tensile stress and inter-connection result in failures. Fracture surfaces coexist ductile and brittle features at lower temperatures, the cleavage failures are observed in a-phase and a lot of ductile fracture features are represented in b-phase. There is no cleavage fracture feature and materials show almost ductile fracture features when the temperature raising upon 100℃. Li-hui Chen Truan-sheng Lui 陳立輝 呂傳盛 2009 學位論文 ; thesis 69 zh-TW
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language zh-TW
format Others
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description 碩士 === 國立成功大學 === 材料科學及工程學系碩博士班 === 97 === Magnesium alloys have many advantages such as low density, high specific strength, good mechanic damping properties and good radiation absorption of electromagnetic waves. They are commonly applied in traffic and electronic industries. Magnesium alloys with adding lithium element could make the density lower than the pure magnesium. This study focuses on tensile properties and ductile to brittle transition characteristics of the two-phase Mg-10Li-2Al-1Zn alloy, which is consist of HCP a-phase and BCC b-phase, at the temperature range of 248K ~ 523K (−25℃~250℃). Tensile testing results show that the ultimate tensile stress and the yield stress decreased with increasing temperatures. The uniform elongation has a maximum value at 50℃. The total elongation is significantly increased at the temperature range of RT~50℃, and it further increases to 55% at 100℃. The ductile to brittle transition behavior is occurred at the temperature range of RT~50℃. Fracture sub-surfaces reveal that initial cracks occurred within a-phase and a/b-phase interfaces. At low temperatures, failures are resulted from cracks propagation and inter-connection rapidly. When the temperature raising upon 50℃, cracks grow into pores by tensile stress and inter-connection result in failures. Fracture surfaces coexist ductile and brittle features at lower temperatures, the cleavage failures are observed in a-phase and a lot of ductile fracture features are represented in b-phase. There is no cleavage fracture feature and materials show almost ductile fracture features when the temperature raising upon 100℃.
author2 Li-hui Chen
author_facet Li-hui Chen
Hao-En Hung
洪浩恩
author Hao-En Hung
洪浩恩
spellingShingle Hao-En Hung
洪浩恩
A Study on the Tensile Properties and Ductile to Brittle Transition Characteristics of Mg-10Li-2Al-1Zn Extruded Alloy at Temperature Range of 248K~523K
author_sort Hao-En Hung
title A Study on the Tensile Properties and Ductile to Brittle Transition Characteristics of Mg-10Li-2Al-1Zn Extruded Alloy at Temperature Range of 248K~523K
title_short A Study on the Tensile Properties and Ductile to Brittle Transition Characteristics of Mg-10Li-2Al-1Zn Extruded Alloy at Temperature Range of 248K~523K
title_full A Study on the Tensile Properties and Ductile to Brittle Transition Characteristics of Mg-10Li-2Al-1Zn Extruded Alloy at Temperature Range of 248K~523K
title_fullStr A Study on the Tensile Properties and Ductile to Brittle Transition Characteristics of Mg-10Li-2Al-1Zn Extruded Alloy at Temperature Range of 248K~523K
title_full_unstemmed A Study on the Tensile Properties and Ductile to Brittle Transition Characteristics of Mg-10Li-2Al-1Zn Extruded Alloy at Temperature Range of 248K~523K
title_sort study on the tensile properties and ductile to brittle transition characteristics of mg-10li-2al-1zn extruded alloy at temperature range of 248k~523k
publishDate 2009
url http://ndltd.ncl.edu.tw/handle/46593779263626706734
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