稀土Y对AZ31镁合金金相组织和力学性能酌影响

研究了稀土元素Y对AZ31镁合金金相组织和力学性能的影响。结果表明：当稀土添加量为0．6％～0．9％时，仅（Mg）基体晶粒变细，并且加入量为0．9％时得到更细化的组织，13相（Mg17Al12）在晶界由连续网状变为断续弥散状分布，由于α（Mg）基体晶粒的细化和p柏形貌的改善，合金的力学性能有提高；当稀土添加量为1．2％时，α（Mg）基体晶粒显著粗化，β相（Mg17Al12）内部出现针状和圆盘状的第二相，力学性能下降。     

稀土Y对AZ31镁合金金相组织和力学性能的影响

研究了稀土元素Y对AZ31镁合金金相组织和力学性能的影响.结果表明当稀土添加量为0.6 %～0.9 %时,α(Mg)基体晶粒变细,并且加入量为0.9 %时得到更细化的组织,β相(Mg17Al12)在晶界由连续网状变为断续弥散状分布,由于α (Mg)基体晶粒的细化和β相形貌的改善,合金的力学性能有提高;当稀土添加量为1.2 %时,α(Mg)基体晶粒显著粗化,β相(Mg17Al12)内部出现针状和圆盘状的第二相,力学性能下降.     

稀土La对AZ31镁合金显微组织和力学性能的影响

研究了稀土元素La对AZ31镁合金组织和力学性能的影响。结果表明:稀土元素的含量能显著改善AZ31镁合金的组织结构,随着含量的增加,α(Mg)基晶粒会变的越来越细小,当La含量达到0.9%时最为细小,均匀,晶粒减小到60.45μm,维式硬度达100.3HV,冲击韧性达到16.2J/cm~2。La的加入会改变β(Mg_(17)Al_(12))相,使β相由连续的网状变为间断弥散分布,并且会在晶界出生成小针状、骨骼状的Al-La化合物AL_(11)La_3替代β相。加强了晶界力,细化了晶粒,最终改善了综合力学性能。对于提高变形镁合金在电子产品中的应用提供了跟广阔的依据。     

稀土钕对AZ31B镁合金铸态组织和性能的影响

通过金相分析、扫描电镜分析及化学成分分析等测试手段,对添加不同含量稀土Nd的AZ31B镁合金的显微组织和力学性能进行了研究.结果表明,稀土Nd的添加,形成了高熔点、高热稳定性的Al4Nd和Mg12Nd稀土相,细化了晶粒;减少了β-Mg17Al12相的数量,改变了β-Mg17Al12相的形态;微量稀土Nd的加入可以提高AZ31B镁合金的强度和塑性,改善合金的力学性能,使其强度达到210MPa,相对于AZ31B镁合金提高了42MPa.     

Sm对AZ80镁合金组织和力学性能的影响

采用真空感应熔炼法制备了AZ80-xSm合金(x=0、0.6、1.0、1.5),研究了不同含量的Sm对AZ80镁合金合金组织和力学性能的影响。通过金相显微镜、扫描电镜、透射电镜、EDS、XRD观察和分析了合金的微观形貌和组织结构,测量了合金抗拉强度和伸长率。结果表明,合金中添加稀土元素Sm后晶粒明显细化;生成颗粒状析出相(Al3Sm),减少合金中β相(Mg l7Al l2)的数量,并使连续网状分布的β相断续,Al3Sm相对合金的强化效果明显优于β相,使AZ80镁合金的力学性能得到提高,其中AZ80-1.0Sm合金抗拉强度达到213 MPa,比原始合金提高了21.7%。     

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％。     

Sr,Y对AZ31镁合金显微组织与力学性能的影响

用金属型铸造法制备了不同Sr、Y含量的AZ31镁合金试样,借助光学显微镜、扫描电镜、能谱分析、XRD、力学性能测试等方法研究了Sr、Y对AZ31镁合金显微组织和力学性能的影响。结果表明,微量Sr的添加可细化AZ31镁合金的显微组织,并且在晶界处有杆状的Al4Sr形成;微量的Sr、Y复合添加可使AZ31镁合金显微组织更加细化,晶内有颗粒状的Al2Y析出,同时β-Mg17Al12相消失;合金的常温和高温力学性能随Sr、Y的添加有明显提高。     

Gd对铸态AZ31合金组织和性能的影响

研究了稀土元素Gd对铸态AZ31镁合金显微组织和力学性能的影响.结果表明,Gd的加入使AZ31合金中出现了颗粒状和块状的Al<,2>Gd相,并使β-Mg<,17>Al<,12>相的含量减少,从而细化了AZ31铸态组织;0.8%的Gd的加入使合金的平均晶粒尺寸从约290μm减小到约140 μm,合金的强度和伸长率分别提高到210 MPa和18.3%.     

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220 MPa,与不含稀土的AZ81相比高温强度约提高40%.     

Cd对AZ31镁合金铸态组织和力学性能的影响

研究了Cd对镁及AZ31镁合金铸态组织和力学性能的影响。在AZ31镁合金中加入微量Cd能够明显地细化基体组织,加入0.7％CdN,其组织由富Al的α-Mg基体和均匀、弥散分布的析出相β—Mg17Al12组成,CdN溶于基体不形成化合物相;使合金的冲击韧性提高了68．6％,布氏硬度提高了10.3％,抗拉强度提高了9％,伸长率提高了35％。     

Al-5Ti-1B对AZ31合金组织与性能的影响

研究了Al-5Ti-1B中间合金不同添加量对AZ31镁合金显微组织和力学性能的影响。结果表明,在AZ31镁合金中添加Al-5Ti-1B中间合金有利于组织性能的改善。在试验中,添加量控制在0.5%为佳,此时,合金晶粒尺寸达到最小,约为170μm,是AZ31镁合金未添加细化剂时晶粒尺寸的30%,抗拉强度及伸长率分别达到最大。AZ31镁合金组织性能的变化主要与Al-5Ti-1B中间合金中的游离Ti和TiB2有关。     

Comparison of corrosion behaviors of AZ31, AZ91, AM60 and ZK60 magnesium alloys

The corrosion behaviours of four kinds of rolled magnesium alloys of AZ31, AZ91, AM60 and ZK60 were studied in 1 mol/L sodium chloride solution. The results of EIS and potentiodynamic polarization show that the corrosion resistance of the four materials is ranked as ZK60＞AM60＞AZ31＞AZ91. The corrosion processes of the four magnesium alloys were also analyzed by SEM and energy dispersive spectroscopy(EDS). The results show that the corrosion patterns of the four alloys are localized corrosion and the galvanic couples formed by the second phase particles and the matrix are the main source of the localized corrosion of magnesium alloys. The corrosion resistance of the different magnesium alloys has direct relationship with the concentration of alloying elements and microstructure of magnesium alloys. The ratio of the β phase in AZ91 is higher than that in AZ31 and the β phase can form micro-galvanic cell with the alloy matrix, as a result, the corrosion resistance of AZ31 will be higher than AZ91. The manganese element in AM60 magnesium alloy can form the second phase particle of AlMnFe, which can reduce the Fe content in magnesium alloy matrix, purifying the microstructure of alloy, as a result, the corrosion resistance of AM60 is improved. However, due to the more noble galvanic couples of AlMnFe and matrix, the microscopic corrosion morphology of AM60 is more localized. The zirconium element in ZK60 magnesium alloy can refine grain, form stable compounds with Fe and Si, and purify the composition of alloy, which results in the good corrosion resistance of ZK60 magnesium alloy.     

退火温度对大变形热轧AZ31镁合金板材力学性能的影响

采用热挤压态AZ31变形镁合金板坯,研究了退火温度对大变形热轧AZ31变形镁合金板材力学性能的影响.结果表明:随着退火温度的升高,变形镁合金板材的抗拉强度和屈服强度减小,伸长率呈线性增加趋势,硬度和杯突值均降低.变形镁合金板材的力学性能与其晶粒尺寸和组织均匀性密切相关.     

铈对镁合金AZ31晶粒大小及铸态力学性能的影响

试验采用普通的熔炼铸造方法，就稀土Ce对镁合金AZ31晶粒大小及其铸态力学性能的影响进行了研究。Ce含量＜1％时随着Ce含量的增加AZ31晶粒越来越细，超过1％时晶粒又变粗。对获得的细晶材料进行了铸态下力学性能的测试并与未加细化剂的材料进行比较，发现抗拉强度和塑性都明显提高。断口扫描分析证明拉伸时断裂为明显的沿晶断裂，压缩时为穿晶断裂。     

累积叠轧温度对AZ31镁合金组织和性能的影响

通过光学显微镜、室温拉伸试验、显微硬度计、X射线衍射仪、扫描电镜等方法研究了累积叠轧温度对AZ31镁合金晶粒尺寸、基面织构、界面结合情况及力学性能的影响。结果表明:3道次累积叠轧后的AZ31镁合金晶粒细化效果明显,硬度增大,随着累积叠轧温度的升高,晶粒细化效果减弱,硬度增加趋势减弱。累积叠轧温度升高有弱化基面织构的作用。AZ31镁合板材在450 ℃累积叠轧3道次,综合力学性能最佳,为显微硬度70.64 HV0.05,抗拉强度288.64 MPa,屈服强度203.76 MPa,伸长率16.96%,界面结合强度21.53 MPa。     

Microstructure and tensile properties of magnesium alloy modified by Si/Ca based refiner

Microstructure and mechanical properties of pure magnesium and AZ31 alloy with Ca/Si based refiner addition were investigated. The results indicate that addition of Ca/Si based refiners to pure magnesium and AZ31 alloy results in remarkable microstructure refinement. With proper amount of refiner addition, the grain size in as cast ingots can be one order of magnitude lower than that without refiner addition. Small amount of refiner addition to AZ31 alloy increases both ultimate strength and yield strength significantly,while the ductility of the alloy with refiner addition is similar to that without refiner addition. Addition of refiner improves the deformability of AZ31 alloy and extruded or hot rolled specimens （rods or sheets） with refiner addition exhibit higher surface quality and mechanical properties than those without refiner addition.     

触变成型镁合金铸件热处理显微组织的演变

通过金相显微镜、SEM及XRD等观察手段研究了触变成型AZ91D镁合金铸件固溶、时效处理时显微组织的演变。结果表明:触变成型AZ91D镁合金在415℃时固溶处理时β相溶解入α-Mg固溶体的速度比高压压铸的快。在固溶处理初期,铝元素从β相扩散至块状初生α-Mg相,导致块状初生α-Mg晶粒周围形成富铝晕圈。时效处理时,触变成型铸件在5h左右硬度达到峰值,高压压铸铸件在12h左右达到峰值。触变成型铸件时效析出方式存在片层状不连续析出和针状连续析出两种。     

Influence of rare earth element Ce and La addition on corrosion behavior of AZ91 magnesium alloy

Two types of AZ91 magnesium alloys containing rare earth element Ce or La were fabricated. Hydrogen evolution and electrochemical tests were carried out to evaluate the corrosion behavior of new AZRE (RE = Ce or La) and AZ91 alloys in 3.5% NaCl solutions (pH 6.50). Various corrosion rate tests indicated that addition of RE obviously enhanced corrosion resistance of AZ91 magnesium alloy. The optimal content of RE was 0.92% for Ce and 0.66% for La. Scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), and low‐angle X‐ray diffraction (XRD) were used to characterize the effect of RE addition on microstructure and corrosion product film of AZ91 magnesium alloy. The refined β phase and formation of γ phase in AZRE alloy were observed by SEM, which resulted in the improvement of corrosion resistance due to the depression of microgalvanic couples. Moreover, the enhanced protective effectiveness of corrosion products was another reason for the improved corrosion resistance.     

高精度AZ31镁合金薄壁管件等温挤压后的组织与性能

研究了不同条件下AZ3l镁合金管材的等温挤压情况,并对挤压前后材料组织与力学性能的变化进行了分析.研究结果表明,AZ31镁合金热挤压时发生了动态再结晶,材料组织比铸态时细化,力学性能大幅度提高;在(653±10)K挤压温度范围内金属流动均匀,挤出管材尺寸精度较高,力学性能良好;从综合性能看,AZ31镁合金挤压产品的合适退火工艺为573 K × 2 h;此时管材的机械拉伸强度为260 MPa,伸长率为23%.     

Nd对AZ31镁合金微观组织与力学性能的影响

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在AZ31合金中的吸收率达95%,Nd加入AZ31合金中形成了Al2Nd和Mg12Nd金属间化合物,Nd使合金的平均晶粒尺寸减小,力学性能提高.含Nd的AZ31合金铸态抗拉强度、屈服强度和伸长率值分别为245 Mpa、171 Mpa和9%.