(1. 重慶大學(xué) 國(guó)家鎂合金材料工程技術(shù)研究中心，重慶 400044；
2. 重慶大學(xué) 材料科學(xué)與工程學(xué)院，重慶 400044)
摘 要: 在氬氣保護(hù)下采用電磁感應(yīng)真空熔煉制備出單一α-Mg相、單一β-Li相及兩相共存的3種不同相態(tài)的Mg-Li二元合金，并運(yùn)用光學(xué)顯微鏡、XRD、阻尼測(cè)試及力學(xué)測(cè)試方法對(duì)合金的組織結(jié)構(gòu)、力學(xué)性能及阻尼性能進(jìn)行分析和討論。結(jié)果表明：Li含量的增加使合金的相態(tài)發(fā)生改變，同時(shí)對(duì)合金起到晶粒細(xì)化的作用，且能有效地提高合金的屈服強(qiáng)度。體心立方結(jié)構(gòu)的β-Li相會(huì)增大合金的臨界應(yīng)變振幅以及阻尼性能，但兩相共存狀態(tài)的Mg-Li合金具有最好的抗拉強(qiáng)度及伸長(zhǎng)率。Mg-Li二元合金的新阻尼機(jī)制是由低溫區(qū)域位錯(cuò)滑移、高溫區(qū)域的晶界滑移以及合金中的晶格畸變這3種阻尼機(jī)制疊加而成。
關(guān)鍵字: Mg-Li合金；彈性模量；力學(xué)性能；阻尼性能
（1. National Engineering Research Center for Magnesium Alloys, Chongqing University, Chongqing 400044, China;
2. College of Materials Science and Engineering, Chongqing University, Chongqing 400044, China）
Abstract:The vacuum induction melting furnace was used to melt the Mg-Li alloys under the protection of argon atmosphere. Three kinds of Mg-Li binary alloys, single α-Mg phase alloy, single β-Li phase alloy and the dual-phase alloy are obtained. The optical microscope (OM), X-ray diffractometer (XRD), scanning electron microscope (SEM), tensile properties test, amplitude-damping test and temperature-damping test were used to analyze the mechanical properties and the damping capacity of Mg-Li alloys with different phases were studied. The results show that the increase of Li content changes the phases of the alloy, and also plays an important role in the grain refinement which can effectively improve the yield strength. The BCC-structured β-Li phase improves the critical stain amplitude and the damping capacity of Mg-Li alloys, and the dual-phase Mg-Li alloy has the best tensile strength and elongation. The new damping mechanism of Mg-Li alloy is superposed by the dislocation gliding at low temperature, grain boundary sliding at high temperature and the lattice distortion.
Key words: Mg-Li alloys; elastic modulus; mechanical property; damping capacity
