Nd对Mg-Al-Ca合金微结构及力学性能影响的研究（英文）

用OM,SEM和XRD等方法研究了挤压态Mg-Al-Ca-x Nd(x=0~1.76,质量分数,%)合金的显微组织和析出相以及该合金在室温和高温下的力学性能。结果表明,Nd的添加会使基体中形成Al2Nd和Al11Nd3相,并且细化Mg-Al-Ca合金的晶粒。随着Nd添加量的增加,Al2Nd和Al11Nd3相的数量也随之增加。当添加1.76%Nd时,合金的平均晶粒尺寸从不含Nd的4.80μm变为2.39μm。由于第二相的析出和晶粒细化,室温下的力学性能也得到改善。随着Nd元素含量的增加,合金的室温抗拉伸强度由267MPa提高到304 MPa,屈服强度从144 MPa提高到203 MPa,延伸率从20.0%下降到16.9%。在150℃时,随着Nd含量的增加,拉伸强度从192 MPa增加到229 MPa,屈服强度从140 MPa增加到159 MPa,伸长率从48.6%下降到29.3%。     

Nd在挤压态AZ31镁合金中的行为及作用

通过金相显微镜、SEM和XRD观察研究挤压态AZ31-xNd镁合金的微观组织和析出相,并测试合金的室温和高温力学性能。结果表明:Nd在合金中以Al2Nd和Mg12Nd化合物形式存在,且随着Nd量的增加,其数量增加;Nd使合金的晶粒细化、室温和高温性能提高。加入0.6%Nd的合金晶粒尺寸由未加Nd时的26μm降至约10μm,加入0.6%Nd合金的室温抗拉强度、屈服强度和伸长率分别为325MPa、247MPa和18.1%。含Nd合金的抗拉强度和屈服强度随温度升高而下降,而伸长率随温度的升高而增加。     

Nd添加对AZ80镁合金显微组织及力学性能的影响(英文)

研究添加稀土元素Nd对AZ80镁合金显微组织及力学性能的影响。结果表明:添加1.0%Nd元素可以有效地改善AZ80合金的铸态组织,其晶粒尺寸由448μm细化至125μm,凝固组织中出现条状的Al11Nd3相和块状的Al2Nd相,且β-Mg17Al12相显著细化,由连续网状变为不连续分布。时效过程中Nd元素的添加抑制了晶界处不连续析出相的出现,并推迟合金时效峰值的出现。在AZ80合金中添加1.0%Nd时,合金的综合力学性能最佳,屈服强度、抗拉强度和伸长率分别为103.7MPa、224.0MPa和8.4%。该合金T6态的屈服强度和抗拉强度分别达到141.1和231.1MPa。     

Nd对铸态Mg-10Gd-0.7Al合金组织和力学性能的影响

采用熔炼铸造法制备了Mg-10Gd-xNd-0.7Al(x=0,1,1.5,2 mass％)合金,通过光学显微镜、X射线衍射仪、扫描电镜、能谱仪和电子拉伸试验机等设备研究了Nd对铸态Mg-10Gd-0.7Al合金组织和力学性能的影响,结合边-边匹配理论讨论了Nd对合金晶粒的细化机理.结果 表明:铸态Mg-10Gd-0.7Al合金的组织由粗大的α-Mg基体、Mg5Gd相和Al2Gd相组成,添加Nd元素后,合金产生了新相Al2Nd和Mg41Nd5,且细化了晶粒;随着Nd添加量的增加,铸态Mg-10Gd-xNd-0.7Al合金的室温拉伸力学性能先升高后降低,当Nd的添加量为1.5 mass％时,合金综合力学性能最好,其抗拉强度为200.32 MPa,屈服强度为175.47 MPa,伸长率为4.43％;加入Nd后,合金的断裂方式由脆性断裂逐渐转变为韧性断裂.     

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.     

Nd改性AZ91合金的显微组织和力学性能

稀土Nd加入AZ91合金中可生成Al-Nd相并细化合金晶粒.Nd含量影响合金中Al-Nd相的种类、形貌、大小和分布,从而改变合金的室温拉伸力学性能.当Nd含量为1.0%时,合金中析出的Al-Nd相主要为针状的Al11Nd3相;当Nd含量为到2.0%时,针状的Al11Nd3相已经比较少,块状的Al2Nd相为主要的Al-Nd相;当Nd含量为到2.5%时,析出的Al-Nd相几乎全部为块状的Al2Nd相.Nd含量由1.0%增加到2.0%时,合金的伸长率、抗拉强度和屈服强度分别增加 33%、14%和4%;Nd含量由1.0%增加到2.5%时,上述三者分别增加44%、18%和6%.     

La对Al-5Mg-0.2Zr合金组织和性能的影响

采用铸锭冶金法制备了含稀土La的Al-Mg-Zr合金,通过金相显微镜、扫描电镜、能谱和X射线衍射及力学性能测试,观察分析了0.2%的La微合金化对Al-5Mg-0.2Zr合金微观组织和力学性能的影响。结果表明,在Al-5Mg-0.2Zr合金中添加0.2%的La能显著细化合金晶粒,合金的平均晶粒尺寸下降到68μm,同时有效地避免了Al3Zr析出相的粗化和偏聚,使合金抗拉强度、屈服强度及伸长率分别增加到了165.5MPa、112.5MPa和7.5%。     

Zn对铸态及ECAP态Mg15Al合金组织与性能的影响

采用XRD、SEM、EDS和拉伸试验,研究添加Zn元素前后铸态和等通道转角挤压(ECAP)态Mg15Al高铝镁合金的组织和力学性能。结果表明,Zn添加到Mg15Al合金中,主要固溶于β-Mg17Al12相,不生成新相。能够促进铸态Mg15Al合金中α-Mg晶粒细化,使β-Mg17Al12相质量分数增加,以及网状化加剧;使ECAP挤压后Mg15Al-1Zn合金中α-Mg基体晶粒平均尺寸由ECAP态Mg15Al合金的11.3μm减少到8.73μm,促进了β-Mg17Al12相的碎化和均匀分布;ECAP挤压能显著提高Mg15Al-1Zn和Mg15Al合金的综合力学性能,ECAP态Mg15Al-1Zn合金的抗拉强度较铸态合金提高了86%,ECAP态Mg15Al合金抗拉强度较铸态提高了60%,而且在屈服强度和塑性变化不大的情况下,ECAP态Mg15Al-1Zn合金比ECAP态Mg15Al合金室温抗拉强度提高了61.8MPa。说明Zn元素添加,能促进ECAP挤压对Mg15Al合金的晶粒细化效果,提高合金的综合力学性能。     

ECAP制备Mg-15Al-xNd合金的显微组织及高温力学性能

采用光学显微镜(OM),场发射扫描电镜(SEM),透射电镜(TEM),X射线衍射分析(XRD)和高温拉伸试验等研究了稀土Nd元素对ECAP态Mg-15Al合金显微组织及高温力学性能的影响。实验结果表明:随着Nd含量的增加,Mg-15Al-x Nd合金平均晶粒尺寸逐渐减小,当Nd含量达到1.5%和4%时,组织中分别出现针状Al11Nd3和不规则块状Al2Nd相。经ECAP挤压四道次后,基体平均晶粒尺寸2~3μm,β-Mg17Al12相显著细化且呈弥散分布状态。稀土Nd元素可以有效改善ECAP态Mg-15Al合金的高温力学性能,当Nd含量为1.5%时,合金在200℃时的屈服强度和抗拉强度由未加Nd时的116 MPa和139 MPa分别提高到148 MPa和172 MPa。ECAP挤压过程中被碎化的高熔点Al-Nd相在高温下对晶界有较强的钉扎作用,表现出显著的细晶强化和弥散强化效果。     

AZ31-xNd镁合金的微观组织与力学性能

研究了Nd 对AZ31镁合金微观组织和力学性能的影响.结果表明,Nd的加入使AZ31合金组织中出现了颗粒状和针状的Al2Nd和Mg12Nd化合物,且高熔点的Al2Nd在合金凝固过程中首先析出;随着温度的降低,完全离异共晶化合物 Mg12Nd相析出;Nd含量为0.6%时合金的平均晶粒尺寸由68 μm降至29 μm,合金的铸态抗拉强度、屈服强度和伸长率最高,分别为245 MPa、171 MPa和9%.     

Microstructure and mechanical properties of Mg-6Al magnesium alloy with yttrium and neodymium

The effects of rare earth (RE) elements Y and Nd on the microstructure and mechanical properties of Mg-6Al magnesium alloy were investigated. The results show that a proper level of RE elements can obviously refine the microstructure of Mg-6Al magnesium alloys, reduce the quantity of/β-Mg17Al12 phase and form Al2Y and AI2Nd phases. The combined addition of Y and Nd dramatically enhances the tensile strength of the alloys in the temperature range of 20-175℃. When the content of RE elements is up to 1.8%, the values of tensile strength at room temperature and at 150℃ simultaneously reach their maximum of 253 MPa and 196 MPa, respectively.The main mechanisms of enhancement in the mechanical properties of Mg-6Al alloy with Y and Nd are the grain refining strengthening and the dispersion strengthening.     

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.     

Microstructures and mechanical properties of Mg-10Ho-0.6Zr-xNd alloys

Mg-10Ho-0.6Zr-xNd (x=0, 1, 3 and 5, mass fraction, %) alloys were prepared by metal mould casting, and the microstructures and mechanical properties were investigated. The results show that the grain size of as-cast alloys reduces and the hardness and strength increase with the increase of Nd content. The alloys are aged followed by solid solution treatment. Mg-10Ho-0.6Zr-3Nd and Mg-10Ho-0.6Zr-5Nd alloys exhibit obvious age hardening response. The hardness value of Mg-10Ho-0.6Zr-5Nd alloy increases from HV104 at as-cast state to HV136 at peak-aged state. The maximum ultimate tensile strength and yield strength of the Mg-10Ho-0.6Zr-5Nd alloy are obtained in at peak-aged state, and the values are 323 MPa, 212 MPa at room temperature, and 258 MPa, 176 MPa at 250 ℃, respectively. The improvement of the tensile strength is mainly attributed to the fine and dispersively distributed plate-shaped β′ metastable phase.     

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     

稀土铈对AZ61变形镁合金组织和力学性能的影响

研究了不同稀土铈含量对AZ61合金显微组织和力学性能的影响.实验发现:加入稀土铈后,AZ61合金铸态组织的β相变少、变细,铸态晶粒细化;大部分铈与铝结合生成高熔点、高热稳定性的稀土相Al4Ce;在热挤压和退火过程中,Al4Ce能够阻碍晶粒或亚晶粒的长大,使晶粒细化.适量的稀土铈提高了挤压态合金的强度、延伸率和显微硬度;而过量的稀土铈则会导致AZ61合金的性能下降;含1.0%稀土铈的挤压态合金可得到最高的抗拉强度308.1MPa、最高屈服强度180.1MPa、最大的显微硬度HV80.5和最高的延伸率14.2%;所有试验合金的断裂方式是解理断裂.     

复合添加Si、Nd元素对Mg-11Li-3Al合金组织与力学性能的影响

利用磁悬浮真空高频感应加热法熔炼高质量的镁锂合金,通过Si、Nd元素复合添加来研究其对Mg-11Li-3Al合金组织与力学性能的影响。结果表明:加入Si、Nd元素后,组织中主要生成Mg_2Si和Al_(11_Nd_3 2种第二相,其中Si的添加能够促使合金组织中形成篆体形貌的黑色析出物聚集区,而Nd的加入能够细化这种黑色棒状的析出物,并减小晶粒尺寸、洁净组织。当Nd的添加量为1%(质量分数)时其晶粒细化的效果最佳。经过XRD和EDS分析发现,这种黑色棒状的析出物为Mg_2Si相和Al_(11)Nd_3相的结合体。铸态合金的抗拉强度随着Si含量的增加递增,最后趋于稳定;其塑性并不会随某一种或是复合元素的添加而单调变化。实验得到了一种综合力学性能最佳的合金Mg-11Li-3Al-1Si-1Nd,其抗拉强度和伸长率分别为212.3 MPa和46.2%。     

Microstructure and mechanical properties of AZ81 magnesium alloy with Y and Nd elements

The effects of rare earth（RE） elements Y and Nd （w（Y）/w（Nd）=3：2） with total content of 1%-4% on microstructures and elevated temperature mechanical properties of AZ81 magnesium alloy were investigated. The results show that, proper content of rare earth elements makes the microstructures of AZ81 magnesium alloy refine obviously and the quantity offl-MglTAll2 phases reduce, and Al2Y and Al2Nd form. After solid solution treatment, with increasing content of rare earth elements, the tensile strength and elongation of the alloys （at room temperature, 150 ℃ and 250 ℃） increase first, then decrease. When the content of rare earth elements is up to 2%, the values of tensile strength at room temperature and 150 ℃ are up to their maxima simultaneously, 282 MPa and 212 MPa, respectively. Meanwhile, the values of elongation at room temperature and at elevated temperature are also up to their maxima, 13% and 15%, respectively.     

Effect of CaC_2 particulates concentration on microstructure and tensile properties of elemental magnesium

CaC_2 particulates reinforced magnesium materials were synthesized using a new technique-electromagnetic suspension casting(ESC).The microstructure and composition of magnesium alloys were investigated and the mechanical properties of alloys were tested.The tensile fracture surfaces were also studied by scanning electron microscopy.And the grain refinement effect of alloys was also examined.The results indicate that proper additions of CaC_2 particulates are found to be efficient in refining the microstr...     

Effects of Yb addition on microstructures and mechanical properties of 2519A aluminum alloy plate

The effects of Yb content on the microstructures and mechanical properties of 2519A aluminum alloy plate were investigated by means of tensile test,optical microscopy,transmission electron microscopy,scanning electron microscopy and X-ray diffractometer.The results show that addition of 0.17% (mass fraction) Yb increases the density of θ' particles of the 2519A alloy plate and reduces the coarsening speed rate of θ' phase at 300 ℃.Therefore,tensile strength is enhanced from 483.2 MPa to 501.0 MPa at room temperature and is improved from 139.5 MPa to 169.4 MPa at 300 ℃.The results also show that with the addition of 0.30% (mass fraction) Yb,the mechanical properties increase at 300 ℃ and decrease at room temperature.With Yb additions,the Al7.4Cu9.6Yb2 phase is found whilst the segregated phases of as-cast alloys along grain boundaries become discontinuous,thin and spheroidized.