Nd对Mg-4Al-1Sr合金显微组织及力学性能的影响

研究了Nd含量(0、1.0%、2.0%、3.0%)对Mg-4Al-1Sr合金显微组织及室温、高温力学性能的影响.研究结果表明,合金中添加Nd后,细化了合金晶粒,形成高熔点的针状强化相Al11Nd3,很大程度上提高了合金力学性能.当Nd含量达到2.0%时,合金的室温、高温抗拉强度分别达到了206 MPa和138 MPa,比未添加Nd时提高了20%和14%.随着Nd含量的进一步增加,合金中析出了大块状Al2Nd相,该相的形成降低了合金的力学性能.     

Mg-5.5Al-0.5Y-xSm合金的显微组织和力学性能

采用XRD、OM、SEM和EDS等手段研究了Mg-5.5Al-0.5Y-xSm(x=0~2.0%)合金的显微组织和力学性能。实验结果表明,加入适量的Sm后,合金晶粒和Al2Y相得到细化,Mg17Al12相数量减少,同时基体中出现高熔点相Al2Sm相。随着Sm含量的增加,合金的室温(25℃)和高温(150℃和175℃)力学性能先升高后降低,且在Sm含量为1%时达到最佳。     

Nd对2519铝合金组织与耐热性能的影响

利用力学性能测试、金相、X射线衍射、扫描电镜与透射电镜等研究微量Nd对2519铝合金组织与力学性能的影响.结果表明:添加0.14% Nd提高合金的强度,硬度最适宜;Nd元素与Cu和Al 元素主要形成Al8Cu4Nd金属间化合物,并沿晶界分布.这些金属间化合物有效地阻碍高温时基体的变形和晶界的迁移,从而提高了合金的高温强度.Nd能细化合金的时效强化相,提高合金力学性能.添加0.14% Nd时,合金在300 ℃时的抗拉强度提高15.4%,室温抗拉强度提高4.4%;当Nd含量进一步增加时,合金室温及高温力学性能降低.     

汽车用AZ31合金的组织与力学性能研究

采用金相显微镜、X射线衍射仪、扫描电镜和力学性能测试等手段,对Nd微合金化的汽车用AZ31合金进行了铸态组织与常温力学性能的研究,并探讨了Nd元素的作用机理。结果表明,在铸态AZ31合金中添加Nd元素可以有效细化合金晶粒尺寸,并在一定程度上增加合金的硬度和力学性能;当合金中Nd元素含量为0.4%时可以取得最佳的强度和塑性结合,继续增加Nd元素含量强度和塑性反而降低。Nd元素的强化作用机理主要为:细晶强化和弥散强化。     

稀土Sm对5086铝合金组织和性能的影响

以5086合金为基础,通过加入稀土元素Sm进行合金化,以期获得室温和高温力学性能优良的耐热铝合金。采用光学显微镜、扫描电镜、X射线衍射仪、电子拉伸试验机等多种分析和测试手段,系统研究了稀土元素Sm对5086合金显微组织及室温和高温力学性能的影响。结果表明,适量稀土元素Sm的加入能够改善5086合金的显微组织,提高其力学性能。随着Sm含量的增加,合金的强度和伸长率先升高后降低,且当Sm的加入量为1.5%时,不论是在室温（20℃）,还是在高温（150℃、175℃）,合金的抗拉强度和伸长率都能取得最大值。     

钐含量对镁合金微观组织和力学性能的影响

借助光学显微镜、扫描电镜和电子万能试验机研究AM90合金中加入钐(Sm)后的显微组织和力学性能,并分析Sm对合金显微组织和力学性能的影响.结果表明:AM90-xSm合金是由α-Mg、β-Mg17Al12和Al2Sm金属间化合物组成.随着Sm含量的增加,β-Mg17Al12相的尺寸减小,AM90-xSm合金的晶粒得到细化.当Sm含量为2.0％时,屈服强度和极限抗拉强度分别达到最大值147MPa和168MPa.当Sm含量为1.0％时伸长率达到最大值,进一步增加Sm的含量时合金的伸长率有所降低.     

稀土Sm对铸态Mg-0.4Zn-0.8Zr合金组织和性能的影响

采用光学显微镜、X射线衍射、扫描电镜、硬度测试和拉伸强度测试对Mg-x Sm-0.4Zn-0.8Zr(x=2,3,4,5)镁合金进行组织观察和力学性能分析。结果表明:合金的显微组织由α-Mg基体和沿晶界分布的第二相Mg41Sm5构成,稀土Sm的加入能够细化晶粒,随着Sm含量的增加,Mg-0.4Zn-0.8Zr合金的硬度提高,当Sm含量为5%时,硬度达最大值,比ZM6镁合金提高9.2%。当Sm含量为3%时,合金抗拉强度达到最大值,比ZM6提高6.3%,当Sm含量超过3%时,抗拉强度降低。     

稀土Nd对铸造Al-Si合金低温拉伸断裂行为的影响

研究了稀土Nd元素对Al-7Si-0.3Mg合金的低温拉伸性能及其断裂行为的影响。结果表明拉伸温度对铸造Al-7Si-0.3Mg的拉伸性能有显著影响,在低温(-60℃)下拉伸,合金的强度提高但伸长率降低。随着Al-7Si-0.3Mg合金中Nd含量的增加,合金在低温(-60℃)下的屈服强度、抗拉强度和伸长率呈现先升高后降低的趋势。Nd元素含量为0.2wt.%时合金力学性能达到最高值,这是由于Nd对组织细化和Si相的变质作用;当合金中Nd含量分别大于0.4%和0.8%后,组织中会形成棒状Al_4Nd相和片状Al_2NdSi_2相,这些脆性相在拉伸时割裂合金基体,使合金的低温拉伸性能降低。     

Nd对Mg-2Ca合金组织和性能的影响

以Mg-2Ca-xNd三元合金为主要研究对象,运用金相分析(OM)、扫描电镜分析(SEM)、能谱分析(EDS)、X射线衍射分析(XRD)及万能拉伸试验机等多种分析和测试手段,系统研究了稀土元素Nd含量对Mg-2Ca-xNd三元合金的显微组织和力学性能的影响.结果表明,随着Nd含量的增加,晶粒变得细小,当Nd含量超过2%时,晶粒又开始变得粗大,并且晶界析出相明显增多,晶内析出大量针状Mg-Nd金属间相.Mg-2Ca-xNd合金的抗拉强度先升高后降低,合金的塑性降低.Mg-2Ca-xNd合金的硬度随着Nd含量的增加而增加.     

Sm对AZ31镁合金力学性能的影响

以AZ31镁合金为基础,通过加入稀土元素Sm(钐)进行合金化,以获得室温和高温力学性能优良的耐热镁合金。采用光学显微镜、扫描电镜、X射线衍射仪、电子拉伸试验机等多种分析和测试手段,较为系统地研究了稀土元素Sm对AZ31镁合金显微组织及室温和高温力学性能的影响。结果表明,适量的稀土元素Sm的加入能够改善AZ31镁合金的显微组织,提高其力学性能。随着钐含量的增加,合金的强度和伸长率先升高后降低,且当w(Sm)=1.5%时,不论是在室温(20℃)还是在高温(150℃、175℃),合金的抗拉强度和伸长率取得最大值。在稀土元素Sm的加入量一定时,合金的抗拉强度随温度的升高而降低。     

Phase structure and electrochemical performances of Co-free La–Mg–Ni-based alloys with Nd/Sm partial substitution for La

In this paper, the Co-free hydrogen storage alloys with the nominal compositions of La0.75R0.05Mg0.20Ni3.40Al0.10(R = La, Nd and Sm) were prepared by induction melting, and then the phase structure and electrochemical properties of these alloys were comparatively investigated. It is found that the alloys mainly consist of(La, Mg)2Ni7phase, La Ni5 phase and(La, Mg)5Ni19phase.Refinement results further show that Nd substitution for La remarkably promotes the formation of La Ni5 phase, while Sm is beneficial for the formation of(La, Mg)5Ni19phase.At discharge current density of 1,875 m A g-1, the highrate dischargeability(HRD) of alloy electrodes increases by 13.9 % and 6.5 % with La substituted by Nd and Sm,respectively. The electrochemical kinetic measurements reveal that the exchange current density(I0), charge transfer resistance(R) and hydrogen diffusion coefficient(D) for the alloy electrode are all facilitated with Nd and Sm partial substitution for La. Subsequently, a linear correlation between the HRD1875 and the corresponding I0/D is found.     

微量稀土Sm对AZ91D显微组织和腐蚀性能的影响

利用扫描电镜 (SEM) 结合能谱分析 (EDS)、X射线衍射 (XRD)、腐蚀失重实验、电化学极化曲线等方法,研究了0.1%,0.4%,0.7%和1.0%的Sm对AZ91D合金的微观组织和腐蚀性能的影响,并对其腐蚀机理进行分析。结果表明：随着Sm含量的增加,合金中粗大的枝状第二相 (β-Mg₁₇Al₁₂) 逐渐断裂变小,其体积分数下降,因为Sm会结合Al形成颗粒状的Al₂Sm和杆状的Al₃Sm,从而减少晶界处第二相的数量,使第二相呈不连续分布;AZ91D的耐腐蚀性随着Sm加入量的增多,先增加后降低;当Sm加入量为1.0%时,合金的耐腐蚀性与不添加Sm的AZ91D接近;Sm的最佳添加量为0.4%。     

Effect of Nd content on microstructure and mechanical properties of as-cast Mg-12Li-3Al alloy

In order to improve the mechanical properties of Mg-Li alloy with single β phase structure, Mg-12Li-3Al-xNd(x=0.3, 0.7, 1.1, 2.0wt.%) alloy was prepared. Subsequently, the as-cast microstructure and mechanical properties were observed and tested. The results showed that the structure of Mg-12Li-3Al-xNd(x=0.3, 0.7, 1.1, 2.0wt.%) as-cast alloy was composed of β phase matrix and Al_2Nd, Al_(11)Nd_3, MgLiAl_2, Al_4Li_9 and AlLi phases. With the increase of Nd content in the alloy, the Al-Nd intermetallic compounds have a trend to change from needle-like Al_(11)Nd_3 to granular Al_2Nd. The hardness of as-cast Mg-12Li-3Al-xNd(x=0.3, 0.7, 1.1, 2.0wt.%) alloy was stable at room temperature. The tensile strength of Mg-12Li-3Al-1.1Nd was as high as 180 MPa, the elongation rate of Mg-12Li-3Al-0.7Nd reached 53.7%, and the comprehensive mechanical properties of Mg-12Li-3Al-2.0Nd was the best. PLC phenomenon occurred during the tensile process of the alloys at room temperature. Therefore, the β-based Mg-Li alloy with good plasticity as well as enhanced strength can be obtained by a moderate addition of Nd and Al.     

不同合金元素对Mg15Al高铝镁合金组织与性能的影响

研究了不同合金元素（Zn,Nd,Si）对Mg15Al镁合金的组织和性能的影响。通过对Mg15Al,Mg15Al1Zn,Mg15Al1Si,Mg15Al1．5Nd四种合金微观组织的观察和力学性能的测定,发现添加了合金元素后Mg合金组织中α—Mg基体和β—Mg17Al12相都得到了不同程度的细化,其中Mg15Al1Si,Mg15Al1．5Nd合金组织中有第三相生成,其形态分别为汉字状、块状,长针状。试验结果表明：添加zn和Nd元素后,抗拉强度比Mg15Al合金显著提高。提高幅度分另4为：13．2％和16．6％,而添加si元素后Mg15Al1Si合金抗拉强度比Mg15Al合金低。添加Nd元素后,伸长率比Mgl5Al合金显著提高,增幅为140％,添加了Si元素和Zn元素后,伸长率比Mg15Al合金低。     

Microstructure and strengthening mechanisms of Mg-6Al-6Nd alloy

The microstructure and strengthening mechanisms of as-cast Mg-6Al-6Nd alloy were studied. The results show that the addition of 6 wt.% Nd into Mg-6Al alloy leads to the precipitation of Al11Nd3 and Al2Nd phases and decrease in the content of Al solid soluted in Mg-Al matrix. The volume fractions of Al11Nd3 and Al2Nd phases are 3.64% and 0.34%, respectively. Compared with Mg-6Al alloy, the ultimate strength, yielding strength, and elongation of Mg-6Al-6Nd alloy at room temperature and 175°C are enhanced in some degrees. The strengthening mechanisms of Mg-6Al-6Nd alloy are mainly composed of solid solution strengthening of Al solid soluted in Mg-Al matrix and grain refinement strengthening, dispersion strengthening, and composite strengthening brought by the precipitation of Al11Nd3 phase. The composite strengthening includes the load transfer from the matrix to Al11Nd3 phase and the enhancement of dislocation density due to the geometrical mismatch and thermal mismatch between the matrix and Al11Nd3 phase.     

Mg-6Al-2Sr-xNd镁合金的显微组织和力学性能

研究了Mg-6Al-2Sr-xNd镁合金的显微组织和常温力学性能,探讨了合金中Nd与Sr复合添加后的存在形式及不同含量的Nd对合金常温力学性能的影响.结果表明：Al4Sr相呈网状沿晶界分布,而Al11Nd3相呈颗粒状或针状,在晶内、晶界均有析出.Al4Sr相在晶界起到了阻止晶界滑移的作用,Al11Nd3相在晶内有钉扎位错的作用,晶界晶内的双重强化提高了合金的强度.合金的抗拉强度、屈服强度和伸长率均在含Nd量为1.0%时达到了峰值.     

Effect of Sm on the microstructure and properties of Mg-9Al alloy

Effect of rare earth Sm on the microstructure and properties of Mg-9Al alloy was investigated. The results indicate that the microstructure of Mg-9Al alloy is refined by the addition of rare earth Sm. The tensile strength, elongation and corrosion resistance of Mg-9Al alloy are increased with increasing Sm. When the content of Sm is 1.0%, the tensile strength and elongation of Mg-9Al alloy are improved from 117.4 MPa and 4.0% to 136.84 MPa and 7.47%, respectively. And the corrosion resistance of Mg-9Al alloy is improved by 26.6% when adding 1.0% Sm. However, the properties of Mg-9Al alloy are decreased with the further addition of Sm.     

Nd对Mg-6Al铸态合金拉伸性能的影响

研究Nd对Mg-6Al铸态合金拉伸性能的影响。结果表明：室温和175 ℃下,Mg-6Al-xNd(x=0,2,4,6,质量分数, 下同)合金的屈服强度随Nd含量增加而增加,在6.0%Nd时达到最大;抗拉强度和延伸率在4.0%Nd时达到最大,当Nd含量上升至6.0%时,两者均有少量下降。组织分析表明,Nd在Mg-6Al中以针状Al11Nd3和多边形状Al2Nd相存在,其中前者含量明显高于后者,为主要析出相。Al11Nd3相析出于枝晶界和晶界,有效细化了枝晶间距和晶粒度。通过建立软硬体复合模型对合金拉伸过程进行力学分析,并结合拉伸断口观察,综合认为Mg-6Al-xNd合金拉伸性能的提高主要归结于Al11Nd3相引起的细晶强化和第二相强化作用。Nd含量达到6.0%时合金抗拉强度和延伸率出现少量下降,主要归结于大块脆性相Al2Nd含量的增加     

Sm对AM60合金显微组织和力学性能的影响

借助光学显微镜、扫描电镜、X射线衍射仪和DNS100电子万能试验机研究AM60合金中加入Sm后的显微组织和力学性能,并分析Sm对合金显微组织和力学性能的影响。结果表明,添加元素Sm可以细化镁合金的晶粒,改变β相的形态和大小,从连续或断续网状、长条状,变为卵石状或颗粒状均匀弥散分布在α-Mg基体上,显著改善合金的显微组织。Sm的加入可形成稳定性较高的颗粒状Al2Sm高温化合物相。随着Sm含量的增加,合金的抗拉伸强度和伸长率呈现先升后降的趋势,当Sm含量为1.0%(质量分数,下同)时抗拉伸强度和伸长率分别达到最大值210MPa和6.9%。室温下AM60合金的断口呈解理断裂,加入Sm变质后其断口形貌表现为准解理+局部韧性断裂特征。     

钕对二元高铝镁合金组织及性能的影响

研究了稀土元素钕对Mg-15Al合金显微组织和力学性能的影响。试验结果表明:加入钕后,Mg-15Al合金的α-Mg晶粒明显细化,α+β共晶组织由粗大网状变得分散、细小,钕与铝结合形成稳定的Al11Nd3,合金的抗拉强度和伸长率均得到显著提高。钕加入量为1.0%时,组织细化效果最好,Mg-15Al合金的综合力学性能达到最佳。当钕加入量为1.5%时,α-Mg晶粒又变大、抗拉强度略有下降。