Sn元素对Mn-44Cu-1.5Al阻尼合金相变机制的影响  

Phase Transformation Mechanism of Mn-44Cu-1.5Al Damping Alloy with Sn Addition

作　　者：郭宇 江震 张松 张入伟 胥永刚[1] Guo Yu;Jiang Zhen;Zhang Song;Zhang Ruwei;Xu Yonggang(Key Laboratory for Advanced Technologies of Materials,The Ministry of Education of China,School of Materials Science and Engineering,Southwest Jiao Tong University,Chengdu 610031,China)

机构地区：[1]西南交通大学材料科学与工程学院材料先进技术教育部重点实验室,四川成都610031

出　　处：《稀有金属》2023年第2期229-235,共7页Chinese Journal of Rare Metals

基　　金：国家自然科学基金项目(11172248);江苏省自然科学基金项目(51701167)资助。

摘　　要：Mn-Cu合金是一种特殊的金属功能材料,能够依靠相界及孪晶界的相对运动耗散振动能量,实现结构的减振降噪。合金元素是影响Mn-Cu合金相变的主要因素之一,但合金元素Sn对合金相变机制的报道却很少。本文以Mn-44Cu-1.5Al以及Mn-43Cu-1.5Al-1Sn阻尼合金为研究对象,通过扫描电镜(SEM)分析了两种合金的成分分布特征;利用电子背散射衍射(EBSD)分析了合金内相的分布情况;利用X射线衍射(XRD)分析了合金的相结构差异;通过多功能内耗仪测试了两种合金的相变点,阻尼性能及其不同激振频率下合金的动态力学谱。结果表明,由于Sn的添加,合金的阻尼性能从0.0142提高至0.055(扭转振幅为2×10^(-4))。其根本原因是Sn元素一方面将合金的马氏体(fct)相变点提高了60.3℃,使合金中的fct相转变量显著增加,从而有效提高了合金组织的相界面积;另一方面,固溶的Sn元素降低了孪晶激活能,增强了合金的孪晶弛豫行为,且相比于0Sn合金,在5~10 Hz范围内1Sn合金的激活能降低了42.71%。此外,由于Sn的原子半径较大,Sn元素进入基体时会提高晶格畸变度从而更有利于马氏体的生成,这使得马氏体相主要分布在晶界附近的富Sn区。研究将有助于理解合金化在Mn-Cu合金阻尼机制中的重要作用。In recent years,the vibration controlling methods were very important for precision instruments in engineering manufacturing industry.High damping alloys,as functional materials,could reduce vibration and noise,thus improving the accuracy of sensors in mechanical equipment.Among the alloys,Mn-Cu based alloys exhibited an excellent damping capacity because of the motion of phase and twin boundaries.The alloying method was often regarded as an efficient way to increase the damping capacity of the alloys.Some research works showed that Sn can effectively promote twin migration in the Cu alloy through first-principles calculations.Therefore,more researches were needed to focus on the role of the Sn elements on the phase transition characteristics and the relaxation performance.Experimentally,the specimens were prepared by induction-melting the pure metals The filamentous specimens (1.5 mm×1.5 mm×6 mm) were cut from the as-cast alloy by electrical discharge machining (EDM),then heat-treated at 100℃for 144 h,followed by quenching in water at room temperature.The crystallization features and composition segregation performance of 0Sn (Mn-44Cu-1.5Al) and 1Sn (Mn-43Cu-1.5Al-1Sn) alloys were analyzed by scanning electron microscopy (SEM,QUANTA FEG 250) using backscattered electron (BSE) imaging.The phase structures of the alloys were analyzed through X-ray diffraction (XRD,Panalytical X’Pert PRO,Cu Kα),and the phase distribution was analyzed by electron backscatter diffraction (EBSD,Quanta 450).Their dynamic mechanical spectrums were measured using a multi-function internal friction device (MFP2000).The exciting frequencies was1,5 and 10 Hz,respectively,the measuring temperature range was from-50 to 150℃and their heating rate was 2.5℃·min-1.The temperature point of tetragonal transition temperature (Tt) of the alloys were also tested,which was used to characterize the phase transformation point of alloys.The variations of damping capacity (internal friction) and relative modulus with the ambient temperature wer

关 键 词：Mn-44Cu-1.5Al合金 Sn元素 内耗 孪晶激活能 

分 类 号：TG135.7[一般工业技术—材料科学与工程]