稀土元素Y、Nd对AZ81镁合金组织和高温性能的影响

研究了稀土元素Y、Nd对AZ81镁合金组织和高温力学性能的影响。结果表明，稀土元素Y、Nd的加入明显细化了AZ81镁合金的显微组织，减少了β（Mg17Al12）相的析出。分析认为，稀土元素Y和Nd主要是通过固溶强化、析出强化和细晶强化提高了合金的室温和高温强度，改善了合金的塑性。复合加入2％的Y和Nd，合金的室温强度最高，达282．5MPa，与未加稀土的AZ81相比，约提高了39％。含1％Y的AZ81合金在150℃下的高温强度高达220MPa，与不含稀土的AZ81相比高温强度约提高40％。     

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.     

La对AZ61镁合金组织及性能的影响

研究添加稀土La含量为(0,0.5,1.0,1.5)％对AZ61合金的微观组织及室温力学性能的影响.结果表明:加入0.5％ ～1.5％的稀土后,铸态AZ61合金组织中的β-Mg17Al12相明显变得细小,形成了针状的Al11La3相.当稀土含量超过1.0％时,针状的Al11 La3相开始粗化长大,β-Mg17 Al12相的网状结构开始分离,变得细小;La的加入可以提高AZ61合金力学性能,当加入的La含量为1.0％时,AZ61合金的力学性能最好.因此,AZ61合金中加入La的质量分数为1.0％时,为合金化的最佳值.     

离心压力对AZ31镁合金的组织和力学性能的影响

通过XRD、压缩试验等方法研究了不同离心压力对AZ31镁合金组织演变和力学性能的影响。结果表明,随着离心压力的增大,离心铸造AZ31镁合金的晶粒明显细化,平衡凝固的共晶转变被抑制,第二相β-Mg17Al12析出量减少,由粗大的“骨骼”状分布转变成弥散分布在晶界,形成以过饱和初生相ɑ-Mg为主相的凝固组织。XRD分析表明,离心压力的增大引起X射线衍射峰向高角度方向偏移,α-Mg的晶格常数减小。随着离心压力的增大,合金力学性能得到明显改善,抗压强度从199 MPa提高到256 MPa,而伸长率变化不明显。     

Effects of Ce addition on microstructure,mechanical properties and corrosion resistance of as-cast AZ80 magnesium alloy

In this study, Ce was introduced into the AZ80 alloy and the effects of Ce addition on the microstructure, mechanical properties and corrosion resistance of the as-cast AZ80 magnesium alloy were investigated. The results show that the addition of Ce into the AZ80 alloy can not only refine the microstructure, but also result in the formation of the needle-like Al4Ce phase. These tiny Al4Ce phases are homogeneously distributed at grain boundaries and within grains. An appropriate Ce addition can also change the β-Mg17Al12 phase at the grain boundaries from continuous network to small island-like. At the same time, with the increase of Ce content from 0 to 2.0wt.%, the macro-hardness of the as-cast alloy is enhanced linearly, while impact toughness, tensile strength and elongation all firstly increase and then decrease. The AZ80 alloy containing 1.0wt.% Ce exhibits the optimal properties. Its macro-hardness, impact toughness, tensile strength and elongation are 61.90 HB, 15.50 J·cm^-2, 171.80 MPa and 3.35%, increase by 9.95%, 63%, 13.3% and 36.7%, respectively compared with the base alloy. In addition, Ce can enhance the corrosion resistance of the AZ80 magnesium alloy.     

稀土铈对AZ61A镁合金组织和力学性能的影响

研究了添加不同含量的稀土Ce对AZ61A镁合金显微组织和力学性能的影响。结果表明,添加适量的稀土Ce能使AZ61A镁合金的基体组织分布均匀,晶粒细化;Ce与Al结合形成高熔点的稀土相Al4Ce,使β-Mg17A112相数量减少,但形态变细;稀土相Al4Ce呈块状或棒状弥散均匀分布于晶界周围,阻碍位错运动,显著改善AZ61A镁合金室温及高温状态下的力学性能。     

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。     

Pb-Sn对压铸AZ81镁合金组织和力学性能的影响

向AZ81镁合金中分别加入0.5%Pb、0.5%Pb+0.5%Sn、0.5%Pb+1.0%Sn合金元素并压铸成型,研究了各成分合金的微观组织和室温、180℃力学性能。结果表明:AZ81-0.5Pb-1.0Sn中存在多边形Mg2Sn,主要分布在晶界;同时,Pb和Sn元素的加入在一定程度上减少了晶界上Mg17Al12的数量,有助于提高镁合金的耐中高温性能;室温下,压铸AZ81-0.5Pb-(0,0.5,1.0)Sn合金抗拉强度和屈服强度随着Sn含量的增加而提高,压铸AZ81-0.5Pb-1.0Sn的抗拉强度为211 MPa、屈服强度为150.5MPa;180℃下,随着Sn含量的增加,抗拉强度和屈服强度均提高,压铸AZ81-0.5Pb-1.0Sn抗拉强度值为200.5 MPa、屈服强度为145.2 MPa;添加元素Pb+Sn使压铸AZ81的180℃断裂机制由塑性断裂向脆性断裂转变。     

Effect of thermal processing on microstructure and mechanical properties of AZ80 magnesium alloy

The influences of deformation temperature and deformation degree on the microstructure and mechanical properties of AZ80 magnesium alloy were investigated by the adoption of isothermal plain strain compression experiment.The results show that thermal compression processing can refine the grain size and the tensile strength of all the deformed AZ80 magnesium alloys is increased to the maximum of 320 MPa.With the increasing of deformation temperature,the tensile strength decreases;with the increasing of th...     

Effect of La and Nd on microstructures and mechanical properties of AZ61 wrought magnesium alloy

Effects of La and Nd addition on the microstructure and mechanical properties of the AZ61 alloy have been investigated. The results show that when La and Nd are added into the AZ61 alloy respectively, the β(Mg17-Al12) phase is refined and granulated, and new phases are formed in the form of small rod-like shape, which are verified as La3 Al12 and Nd3Al11 phase by X-ray diffraction and TEM observation. Microstructure observations show that the effective efficiency of La addition is higher than that of Nd addition, thus the sizes of β(Mg17 Al12) and La3Al11 phase are relatively smaller than those of β(Mg17 Al12 ) and Nd3 Al11 phases in both AZ61 alloy and Nd-containing alloy. The increase of the tensile strength and elongation of AZ61 alloy refers to the existence of small rod-like La3Al11 and Nd3Al11 phases, and fine granulated β(Mg17 Al12 ) phase.     

流变轧制AZ91合金的热处理和组织性能调控

本文对连续流变轧制AZ91合金在热处理过程中的组织和力学性能演化进行了研究。热处理后两种析出相在基体中出现：一种是晶界处的非连续析出相,另一种是从过饱和基体中析出的小尺寸连续析出相。随着时效温度升高,原子扩散速度也随之提高,导致更多的析出相生成和长大。合金的维氏硬度和拉伸强度峰值在16小时时效后出现,而合金的延伸率随着时效时间的延长和时效温度的提高呈下降趋势。经过对实验结果的分析,适合提升合金综合力学性能的热处理制度为415°C固溶20小时加220°C时效16小时。经热处理后得到的维氏硬度、拉伸强度和延伸率分别为：99 HV,251 MPa和4.5%,各项性能均显著优于流变轧制态合金。相对于传统成型手段,流变轧制加热处理方法成型的AZ91合金展现了优异且均衡的综合力学性能。     

La-Ce混合稀土对AZ91D合金组织和性能的影响

以AZ91D镁合金作为研究对象,探究了La-Ce混合稀土含量对其组织性能的影响。结果表明:在AZ91D镁合金中加入混合稀土La-Ce后,铸态组织为网状β-Mg₁₇Al₁₂相及少量杆状稀土化合物。且随着稀土含量增多,β-Mg₁₇Al₁₂和杆状稀土化合物被细化。经固溶时效处理后,随稀土含量增加,试验合金伸长率增大,硬度和抗拉强度均先增后降,稀土含量为2.38%时,合金力学性能最佳。     

Mg2Si强化相对AZ31镁合金挤压组织与力学性能的影响

通过Al-Si中间合金取代Al添加,并经热挤压成形,在AZ31镁合金中引入Mg₂Si强化相。采用光学显微镜(OM)、扫描电镜(SEM)、X射线衍射分析(XRD)、电子万能试验机等研究了Mg₂Si强化相对AZ31镁合金挤压组织与力学性能的影响。结果表明,添加Al-Si中间合金后的Mg-3(Al-Si)-Zn挤压组织呈现明显的双峰分布特征,Mg₂Si颗粒相可通过粒子激发形核(PSN)作用促进动态再结晶,在碎化的Mg₂Si颗粒相周围,合金组织显著细化,形成明显异于其他正常尺寸晶粒的细晶区。引入Mg₂Si强化相后,Mg-3(Al-Si)-Zn挤压态合金的屈服强度和抗拉强度都得到提高,分别达到175和269 MPa,同时伸长率略有降低。     

轧制工艺对AZ31B镁合金薄板组织与性能的影响

研究了轧制温度和轧制速度对AZ31B镁合金薄板微观组织演变和力学性能的影响。结果表明,轧辊加热有利于镁合金薄板成型;AZ31B镁合金在低温或低速轧制时薄板纵向组织为大量的切变带,切变带区域包含大量孪晶组织,横向组织为含极少量孪晶的等轴晶组织;在轧制温度为400℃和轧制速度为16m/min轧制时,由于动态再结晶,横纵截面组织均为等轴晶。AZ31镁合金薄板的最佳轧制制度为轧辊温度为70℃、轧制温度为400℃、轧制速度为6m/min,此工艺轧制的薄板横向抗拉强度、屈服强度和伸长率分别为350MPa、300MPa和12%,纵向为345MPa、290MPa和11.2%,纵向与横向性能差别明显减小。     

Inhomogeneity of microstructure and mechanical properties of a 500 mm diameter heavy section semi-continuous cast AZ61 magnesium alloy ingot简

For the large magnesium alloy ingot, there is a considerable difference in cooling rate of different parts in the ingot, which leads to non-uniform distribution of the secondary phases, solute segregation and tensile properties. In the present research, an heavy AZ61 alloy ingot with a diameter of 500 mm was made by semi-continuous casting. The microstructure and mechanical properties at different positions along the radial direction of the large ingot were investigated by using an optical microscope(OM), a scanning electron microscope(SEM), an energy dispersive spectroscope(EDS), and a micro-hardness tester. The results indicate that the microstructure of the AZ61 ingot is non-uniform in different locations. It changes from equiaxed to columnar grains from the center to the edge; the average grain size gradually reduces from 1,005 μm to 763 μm, the secondary dendrite arm spacing reduces from 78 μm to 50 μm, and the Mg17(Al,Zn)12 phase is also refined. The micro-hardness value increases from 55.4 HV at the center to 72.5 HV at the edge of the ingot due to the microstructure differences, and the distribution of micro-hardness at the edge of the ingot is more uniform than that in the center. The tensile properties at room temperature show little difference from the center to the edge of the ingot except that the elongation at the edge is only 3.5%, much lower than that at other areas. The fracture mechanism is ductile fracture at the center and cleavage fracture at the edge of the ingot, and at the 1/2 radius of the ingot, a mixture of ductile and cleavage fracture is present.     

Ca对AZ81镁合金高温性能的影响

通过合金制备、微观分析和力学性能测试等方法研究了碱土元素Ca对AZ81镁合金微观组织和力学性能的影响。结果表明,加入适量碱土元素Ca后使AZ81镁合金的组织明显细化,β（Mg17Al12）相减少,并析出粒状的化合物Al4Ca。经固溶时效处理后,随着碱土元素含量增加。在室温、150℃和175℃三个温度下。合金的强度和延伸率基本上呈先升后降的趋势。当Ca含量为1％时,合金的室温强度和150℃强度同时达到最大值。分别为224．462MPa和183．542MPa。在各温度下对应的延伸率分别是9．2％和11．34％。     

挤压铸造压力对Mg-Al-Ca镁合金组织及力学性能的影响

利用金相显微镜、显微硬度计及拉伸试验机对不同压力挤压铸造Mg-Al-Ca合金的组织和性能进行了研究。结果表明,提高压力降低了挤压铸造合金中第二相的比例及其孔隙率。在30 MPa以下,随着压力的提高,合金的伸长率、抗拉强度、显微硬度和屈服强度均逐渐提高,在高压下挤压铸造合金的韧性较佳。     

机械振动对铸造铝合金组织和性能的影响

分析振动方式对ZL101铝合金消失模铸件组织和力学性能的影响。结果表明,机械振动后合金组织明显细化;垂直振动时,合金晶粒尺寸最小,孔隙率最低,抗拉强度最大;ZL101合金垂直振动后,不同厚度处的组织存在较大差别,厚度越大,振动细化效果越显著。     

电磁铸造对AZ91D合金组织及力学性能的影响

研究了电磁场对AZ91D合金组织的影响 ,分析和测试了AZ91D合金挤压变形后的组织及性能。结果表明 :电磁搅拌使AZ91D合金枝晶组织发生球化和细化 ,β Mg17Al12 相数量增加 ,并使Zn元素在 β Mg17Al12 相的偏聚倾向降低 ;挤压成形后的合金极限抗拉强度高达 2 85MPa,比压铸合金提高 30 %,延伸率为 12 %,是压铸合金的 2倍多。