摘 要

鎂合金，作為21世紀(jì)的綠色金屬結(jié)構(gòu)材料，具有比重輕、比強(qiáng)度高、阻尼性、減震性及切屑加工性、導(dǎo)熱導(dǎo)電性好、電磁屏蔽能力強(qiáng)、可回收等一系列優(yōu)點(diǎn)，加之人們對(duì)環(huán)保意識(shí)的增強(qiáng)和對(duì)汽車輕型化的需求，鎂正受到人們?cè)絹碓蕉嗟年P(guān)注。用于制造輪轂常用的鎂合金材料為AM60，但該合金的強(qiáng)度低，不能夠滿足輪轂在不同工作環(huán)境中的使用要求。
本文以AM60B為基體，通過改變Al, Zn含量和加入一定量的稀土元素Ce，用擠壓鑄造的方法，制造成為AZ71E鎂合金，然后對(duì)這兩種材料對(duì)比進(jìn)行鑄態(tài)組織金相分析和力學(xué)性能測(cè)試。實(shí)驗(yàn)結(jié)果發(fā)現(xiàn)，AZ71E的微觀組織和綜合性能比AM60B得到較大改善，微觀組織均勻，晶粒細(xì)小，材料的抗拉強(qiáng)度 b為261.71MPa，屈服強(qiáng)度 0.2為157.29MPa，硬度70.05HRE,分別提高了4.8%,13.3%和15.3%，而延伸率為10.06%，下降了12.8%，進(jìn)而更適合于制造輪轂。


關(guān)鍵詞：鎂合金、AM60B、AZ71E、擠壓鑄造、金相組織、力學(xué)性能

Abstract
As a “green” structural material for 21st century, the magnesium alloys have a series of excellent characteristics, such as low specific density, high specific strength and rigidity, better damping capacity, good casting properties, excellent thermal conductivity and electromagnetic shielding, and easy to recycle, etc. In addition, with higher awareness of environmental protection and increased needs for lower weight of automobile, researchers are now paying much attention to the magnesium alloys. AM60, a magnesium alloy, is often used to make wheel hubs. However, this alloy can not be commonly used in different circumstances because of lower strength.
This paper is focused on study of a new Mg alloy called AZ71E made from AM60B by changing the Al, Zn composition of AM60B and addition of rare earth Ce. The new alloy AZ71E was squeeze cast together with AM60B, followed by microstructure analysis and mechanical properties test. It is concluded that the microstructure and properties of AZ71E are improved a lot. For ZA71E, uniform microstructure and small grains have been obtained, the tensile strength is 261.71MPa, the yield strength is 96.32MPa and the hardness is 70.05HRE, which increase 4.8%, 13.3% and 15.3% respectively in comparison with AM60. The elongation of AZ71E is 10.06%, decreased 12.8% compared with AM60. Thus, the new alloy AZ71E is more suitable for wheel hubs.


Key words: Magnesium Alloy, AM60B, AZ71E, squeeze casting, metallurgical structure, mechanical property.










目 錄
中文摘要 1
ABSTRACT 2
1 緒 論 5
1.1 引言 5
1.2 鎂合金材料的研究現(xiàn)狀 6
1.2.1 鎂及鎂合金 5
1.2.2 鎂的提取和制備 7
1.2.3 鎂合金的熔煉和保護(hù) 8
1.3 鎂的成型技術(shù)及發(fā)展現(xiàn)狀 10
1.3.1 壓鑄 10
1.3.2 半固態(tài)鑄造 11
1.3.3 擠壓鑄造 11
1.3.4 鎂合金超塑性 11
1.3.5 沖鍛成型 11
2 試驗(yàn)材料及研究方法 16
2.1 試驗(yàn)材料的選擇 16
2.1.1 鎂中添加合金元素的作用 16
2.2 鎂合金的擠壓成型 18
2.2.1 擠壓成型簡(jiǎn)介 18
2.2.2 擠壓鑄造參數(shù)的認(rèn)識(shí) 20
3 試驗(yàn)準(zhǔn)備及試驗(yàn)過程 21
3.1試驗(yàn)用鎂合金材料 21
3.2試驗(yàn)用鎂合金材料的制備 21
3.2.1 鎂合金的熔煉工藝 21
3.2.2 鎂合金澆注工藝 22
3.3 擠壓鑄造鎂合金參數(shù)的選擇 22
3.4 力學(xué)性能測(cè)試 23
3.4.1 拉伸性能測(cè)試 23
3.4.2 硬度測(cè)試 23
3.5 微觀組織分析 24
4 實(shí)驗(yàn)結(jié)果及分析 25
4.1擠壓鑄造AM60B和AZ71E的顯微組織 25
4.2擠壓鑄造AM60B和AZ71E的力學(xué)性能 26
5 結(jié) 論 26
參考文獻(xiàn) 30