文章信息/Info

Title:

Mechanical Properties and Microstructural Evolution of a Superlight Mg-9.3Li-1.79Al-1.61Zn Alloy

作者:

曹富榮; 夏飛

東北大學(xué)材料科學(xué)與工程學(xué)院，遼寧 沈陽

Author(s):

CAO Furong; XIA Fei

School of Materials Science and Engineering, Northeastern University, Shenyang 110819, China

關(guān)鍵詞:

Mg-Li合金; 軋制; 力學(xué)性能; 顯微組織

Keywords:

magnesium-lithium alloy;  rolling;  mechanical property;  microstructure

文獻標(biāo)志碼:

A

摘要:

為了提高Mg-Li合金的強度和塑性，通過鑄造和軋制方法制備了新型Mg-9.3Li-1.79Al-1.61Zn合金板材，采用光學(xué)顯微鏡、X射線衍射儀(XRD)、透射電子顯微鏡(TEM)、掃描電子顯微鏡(SEM)、顯微硬度計與拉伸試驗機研究了合金的顯微組織和力學(xué)性能。維氏顯微硬度測試發(fā)現(xiàn)冷軋態(tài)的硬度最高。拉伸試驗獲得冷軋合金的延伸率為24%，抗拉強度為209 MPa。光學(xué)組織研究確定熱軋組織為帶狀晶粒組織；冷軋板573 K 經(jīng)1 h退火后，并未發(fā)生完全再結(jié)晶。通過取向分布（ODF）函數(shù)分析熱軋、冷軋和退火過程形成的織構(gòu)，發(fā)現(xiàn)β�睱i相比α�睲g相產(chǎn)生了更多的織構(gòu)分量，但是織構(gòu)強度相對較低。TEM觀察發(fā)現(xiàn)變形組織中Al2Mn相、退火組織中AlLi相的存在。XRD分析進一步證實了退火組織中存在AlLi相。SEM斷口分析表明合金的斷裂形式為韌性斷裂。力學(xué)性能結(jié)果與顯微組織演變一致。

Abstract:

To improve the strength and ductility of Mg-Li alloy, sheets of a novel Mg-9.3Li-1.79Al-1.61Zn alloy were produced by casting and rolling. The microstructures and mechanical properties of the alloy were investigated by optical microscope, X�瞨ay diffractometer (XRD), transmission electron microscope (TEM), scanning electron microscope(SEM), microhardness tester and tensile tester. Microhardness tests reveal that the hardness of the cold�瞨olled sheet reaches the highest value. Tensile tests show that the elongation to failure of 24% and the ultimate tensile strength of 209 MPa were obtained in the cold�瞨olled alloy. Optical microstructural examination exhibits that hot�瞨olled microstructures are composed of banded or elongated grains. After annealing at 573 K for 1 h for the cold�瞨olled sheet, the alloy is in a partially recrystallized state. Oriental distribution function (ODF) maps were used to analyze the textures of duplex phases formed during hot rolling, cold rolling and annealing, we found that more texture components exist in the β�睱i phase than those of the α�睲g phase and the texture intensity of the β�睱i phase is relatively lower. TEM observations reveal the existence of Al2Mn phase in the tensile specimen and the existence of AlLi phase in the as�瞐nnealed microstructure. XRD analysis further confirms the existence of the AlLi phases. SEM examination of the fracture surface of tensile specimen reveals that its fracture mode is a ductile fracture. Above mentioned results of mechanical properties are consistent with the microstructural evolution.