Gd对ZK60镁合金组织与力学性能的影响

分析了铸态和挤压态ZK60?xGd(x=0~4)合金的组织和相组成,测试了其拉伸力学性能。结果表明,随着Gd含量的增加,铸态组织逐渐细化,Mg?Zn?Gd新相逐渐增多,而MgZn2相逐渐减少直至消失,第二相趋于连续网状分布于晶界处;当 Gd 含量不超过2.98%时,铸态室温拉伸力学性能稍降低。经挤压比λ=40和挤压温度T=593 K的挤压后,组织显著细化,平均晶粒尺寸逐渐减至ZK60?2.98Gd合金的2μm,破碎的第二相沿着挤压方向呈带状分布;挤压态的拉伸力学性能均显著提高：298和473 K时的抗拉强度分别从ZK60合金的355和120 MPa逐渐提高至ZK60?2.98Gd合金的380和164 MPa。挤压态拉伸断口呈现典型的韧性断裂特征。     

Zn含量对7XXX铝合金性能及微观组织影响

为了深入研究7XXX铝合金的成分对材料性能的影响,对通过模铸工艺制备的高锌含量的铝基合金性能和微观组织进行了研究,重点探讨了Zn含量对合金组织、性能和铸造流动性的影响。研究结果表明,当Zn含量从20%增加到40%时:对材料组织的影响主要表现为晶粒尺寸由45μm减小到20μm,晶界处非平衡相α+η的体积分数由9%增加到28%;对力学性能的影响表现为抗拉强度与屈服强度升高,分别达到470 MPa和430 MPa,伸长率有所降低,从7%降低至3%左右,合金硬度值由75 HV提高至140 HV。同时,Zn含量的增加可以降低合金固相线温度,这有利于提高合金的流动性。     

Effect of Zn content on microstructure, mechanical properties and fracture behavior of Mg-Mn alloy

The optical microscope, scanning electron microscope and universal testing machine are used to investigate the effect of Zn content on the microstructure, mechanical properties and fracture behavior of Mg-Mn-Zn alloy. The results indicate that fine (Mg, Mn, Al)-containing phases are distributed uniformly in the Mg-Mn alloy matrix, while small amount of (Mg, Zn)-containing phases are formed in the matrix and the grain boundary becomes coarse when 1wt.% Zn is added. As the Zn content increases, the amount of (Mg, Zn)-containing phases increases, and the grain boundary becomes coarser. When the Zn content is between 3wt.%-5wt.%, slender (Mg, Zn)-containing phases precipitate at the grain boundary. The addition of Zn could reduce the grain size and enhance the mechanical properties of the alloy matrix, and both of the effects can be enhanced by increasing the Zn content further more. When the Zn content is more than 3wt.%, grain size stops decrease, the strength cannot be improved any more and elongation decreases significantly. The fracture behavior of Mg-Mn alloy appears to be cleavage fracture, and transforms into quasi-cleavage fracture as Zn is added. When Zn content exceeded 3wt.%, large amount of (Mg, Zn)-containing phases appear on the fracture face, and act as the crack sources.     

微量B对Mg-3A1-1Zn镁合金组织和性能的影响

B通过Al-3B中间舍金加入Mg-3Al-1Zn舍金中，利用OM、XRD及力学性能测试、极化曲线测定等手段对不同B加入量合金的组织和性能进行了分析。实验结果表明，合金的组织随着B加入量的增加变得粗大，当B加入量为0．05％时出现粗大枝晶，0．1％时枝晶进一步长大且出现二次枝晶。舍金的力学性能和耐腐蚀性能也随B加入量的增加而降低。     

铸造冷却速度对Mg-4.4Zn-0.3Zr-0.4Y挤压态合金组织性能的影响

本文通过两种不同冷却速度制备成分相同、铸造组织特征不同的Mg-4.4Zn-0.3Zr-0.4Y铸态合金,研究不同铸造组织特征对挤压变形态合金组织和力学性能的影响。研究结果表明：与空冷铸造合金相比较,通过水冷冷却增大了熔体冷却速度,使铸态组织得到细化,抑制了W-相（Mg3Y2Zn3相）的形核,并促进了I-相（Mg3YZn6相）的生成,获得了更大体积分数的准晶相(I-相)。经过挤压变形后,水冷铸造合金中的再结晶晶粒细小均匀,经过挤压变形破碎的细小I-相颗粒弥散分布在基体上,{0002}基面织构得到弱化,而{101 ?2}织构强度增强,从而使挤压态Mg-4.4Zn-0.3Zr-0.4Y合金的强度和塑性都得到了大幅的提高。水冷铸造Mg-4.4Zn-0.3Zr-0.4Y合金经过挤压变形后,屈服强度和抗拉强度分别达到297.0MPa和327.3MPa,与空冷铸造挤压态合金相比分别提高了46.4MPa和21.4MPa。水冷铸造Mg-4.4Zn-0.3Zr-0.4Y挤压态合金的延伸率达到14.8%,与空冷铸造挤压态合金相比增大了4.7%。     

Microstructure,anticorrosion, biocompatibility and antibacterial activities of extruded Mg−Zn−Mn strengthened with Ca

To find suitable biodegradable materials for implant applications, Mg?6Zn?0.3Mn?xCa (x=0, 0.2 and 0.5, wt.%) alloys were prepared by semi-continuous casting followed by hot-extrusion technique. The microstructure and mechanical properties of Mg?6Zn?0.3Mn?xCa alloys were investigated using the optical microscope, scanning electron microscope and tensile testing. Results indicated that minor Ca addition can slightly refine grains of the extruded Mg?6Zn?0.3Mn alloy and improve its strength. When 0.2 wt.% and 0.5 wt.% Ca were added, the grain sizes of the as-extruded alloys were refined from 4.8 to 4.6 and 4.2 μm, respectively. Of the three alloys studied, the alloy with 0.5 wt.% Ca exhibits better combined mechanical properties with the ultimate tensile strength and elongation of 334 MPa and 20.3%. The corrosion behaviour, cell viability and antibacterial activities of alloys studied were also evaluated. Increasing Ca content deteriorates the corrosion resistance of alloys due to the increase of amount of effective cathodic sites caused by the formation of more Ca₂Mg₆Zn₃ phases. Cytotoxicity evaluation with L929 cells shows higher cell viability of the Mg?6Zn?0.3Mn?0.5Ca alloy compared to Mg?6Zn?0.3Mn and Mg?6Zn?0.3Mn? 0.2Ca alloys. The antibacterial activity against Staphylococcus aureus is enhanced with increasing the Ca content due to its physicochemical and biological performance in bone repairing process.     

Ti含量对AZ61镁合金组织和性能的影响

以AZ61镁合金为研究对象,添加K₂TiF₆与Mg发生原位自生反应生成Ti,采用OM、SEM观察和XRD物相分析以及拉伸性能测试等分析方法,研究了微量Ti对AZ61镁合金组织和性能的影响。研究发现,随着Ti含量的增加,AZ61合金晶粒尺寸先减小后增大,当Ti含量为1.5%时,细化效果最佳,铸态晶粒尺寸为41 μm。铸态和热处理态试样的抗拉强度和伸长率先增大后减小,最高抗拉强度分别达到201.5 MPa和223.5 MPa。     

Effects of Y on mechanical properties and damping capacity of ZK60 magnesium alloys

The microstructure,mechanical properties and damping capacity of ZK60-xY(x=0,1.5%,2.5%,4.0%,mass fraction) magnesium alloys were investigated by using the optical microscope(OM),X-ray diffractometer(XRD),universal tensile testing machine and dynamic mechanical analyzer(DMA).The mechanisms for damping capacity of referred alloys were discussed by Granato-Lücke theory.The results show that Y additions remarkably reduce grain size(the average grain size is 21.6,13.0,8.6 and 4.0μm,respectively),and the tensile properties are enhanced with grain refining(the yield tensile strength increases to 292 MPa from 210 MPa and ultimate tensile strength increases to 330 MPa from 315 MPa).For the ZK60-xY(x=0,1.5%,4.0%)alloys,the damping capacity decreases with the increase of Y content.However,for the ZK60-xY(x=2.5%)alloy,the damping capacity improves abnormally,which is possibly related to the formation of Mg3Y2Zn3(W)FCC phase in this alloy.     

铸态Ti-20Zr-10Nb-xMo合金的微观组织和耐腐蚀性能

采用X射线衍射仪(XRD)、光学显微镜(OM)、硬度测试、压缩试验和电化学工作站等研究了Mo含量对Ti-20Zr-10Nb-xMo(x=0,3,6,9,wt%)合金相结构、显微组织、力学性能以及电化学腐蚀性能的影响。结果表明,随着Mo含量的增加,Ti-20Zr-10Nb-xMo合金的相结构发生了α′+β→α″+β→β的变化,平均晶粒尺寸亦随着Mo含量的增加而逐渐降低;当Mo含量为9%时,合金的平均晶粒尺寸约为45 μm。通过Mo的添加,合金的抗压强度和屈服强度呈现先降低后升高的趋势,而显微硬度则先增大后降低;当Mo含量为9%时,合金的抗压强度最大,为1610 MPa,压缩应变为50.9%。未添加Mo的试验合金的自腐蚀电流密度最小,为33.19 nA·cm^-2,R_p值最大,为1531.52 kΩ·cm²,其耐腐蚀性最好。     

连铸AZ31镁合金的热挤压变形组织与性能(英文)

文章研究了电磁连铸AZ31镁合金经热挤压变形后的微观组织和力学性能。结果表明,挤压过程中的动态再结晶能够显著细化晶粒,局部细晶区的平均晶粒为2μm。与铸态合金相比,挤压后的AZ31镁合金具有更细小的晶粒和更均匀的微观组织。挤压变形后产生强烈的基面织构;挤压后材料的力学性能显著提高。屈服强度、抗拉强度和断面收缩率随着挤压比的增大而增大。挤压比为25时,屈服强度、抗拉强度和断面收缩率分别为259MPa,357MPa和30.5%,比铸态合金分别提高了86.33%,64.52%和67.40%。随着挤压比的增大,晶粒细化效果更为明显,微观组织更均匀。断口形貌分析表明,挤压变形后材料由韧脆混合型断裂,转变为韧性断裂。     

固溶处理对喷射成形1420铝锂合金组织和性能的影响

对喷射成形挤压态的1420铝锂合金进行不同温度、不同时间的固溶处理。采用光学显微镜(OM)、扫描电镜(SEM)、能谱仪(EDS)、X射线衍射仪(XRD)和电子万能试验机对合金的显微组织和力学性能进行分析。结果表明:挤压态合金中分布着大量Al₃Li、AlLi粒子。经450 ℃×0.5 h固溶处理后可获得细小的组织和良好的综合力学性能;第二相颗粒基本溶入合金基体中,抗拉强度为377.47 MPa,伸长率为17.3%,晶粒平均尺寸为2.91 μm;合金的断裂方式为韧性断裂。随着固溶温度、时间的增加,裂纹起源于合金缺陷处,以穿晶的方式扩展。     

稀土元素Dy对Mg-2Zn-0.5Zr生物镁合金组织与性能的影响

通过拉伸试验、浸泡实验、电化学测试、扫描电镜(SEM)以及光学显微镜(OM)等方法研究了Dy含量对Mg-2Zn-0.5Zr-xDy生物镁合金微观组织、耐腐蚀性能和力学性能的影响。结果表明:随Dy含量的增加,合金的晶粒尺寸逐渐变小,第二相逐渐增多且主要沿晶界分布,合金的平均腐蚀速率先降低后升高,合金的力学性能先升高后降低;当Dy含量为1.5 mass%时,合金的耐蚀性能和综合力学性能均最好,平均腐蚀速率从未添加稀土元素时的1.28 mm/a降为0.92 mm/a,抗拉强度和伸长率分别为154 MPa和8.6%。     

Influence of thermo hydrogen treatment on microstructure and mechanical properties of Ti-5Al-2.5Sn ELI alloy

Thermo hydrogen treatment(THT) of titanium is a process in which hydrogen is used as a temporary alloying element in titanium alloys. It is an attractive approach for controlling the microstructure and thereby improving the final mechanical properties. In the present study, the microstructure of the original(non-hydrogenated) sample has only α phase and the grains is coarse with an average size of ~ 650 μm. While the grain size of thermo hydrogen treated Ti-5Al-2.5Sn ELI alloy became finer and the mechanical properties were improved significantly. When the hydrogen content of the hydrogenated Ti-5Al-2.5Sn ELI alloy is 0.321 wt.%, β phase and δ titanium hydride appear. Also the average grain size decreases to 450 μm. When the hydrogen content is 0.515 wt.%, the grain size decreases to 220 μm. The mechanical properties were tested after dehydrogenation, and the mechanical properties improved significantly compared to the unhydrogenated specimens. The tensile strength of the Ti-5Al-2.5Sn ELI alloy improved by 17.7% when the hydrogen content increased to 0.920 wt.%, at the same time the percentage reduction of area(Z) increased by 33% and the impact toughness increased by 37%.     

Microstructures and tensile properties of as-extruded Mg-Sn binary alloys

The microstructure and mechanical properties of Mg-xSn(x=3,7 and 14,mass fraction,%) alloys extruded indirectly at 300℃ were investigated by means of optical microscopy,scanning electron microscopy and tensile test.The grain size of theα-Mg matrix decreases from 220,160 and 93μm after the homogenization treatment to 28,3 and 16μm in the three alloys after extrusion,respectively.The results show that the grain refinement is most remarkable in the as-extruded Mg-7Sn alloy.At the same time,the amount of the Mg2Sn particles remarkably increases in the Mg-7Sn alloy with very uniform distribution in theα-Mg matrix.In contrast,the Mg2Sn phase inherited from the solidification with a large size is mainly distributed along grain boundary in the Mg-14Sn alloy.The tensile tests at room temperature show that the ultimate tensile strength of the as-extruded Mg-7Sn alloy is the highest,i.e.,255 MPa,increased by 120%as compared with that of as-cast samples.     

喷射成形Al—Zn—Mg—Cu系高强铝合金的组织与性能

利用喷射成形工艺制备了Al-Zn-Mg-Cu系高强铝合金材料,研究了热挤压工艺与热处理工艺对材料微观组织与力学性能的影响,在峰时效的情况下材料表现出了高的力学性能指标,抗拉强度达到754MPa,屈服强度达到722ＭＰa,断裂延伸率达到8%,与采用传统铸造变形工艺制备的同类合金相比（σb≥610MPa,σ0.2≥580MPa,δ≥4%),性能有了明显的提高。合金性能的提高与其基体中呈弥散分布的Mg7Zn3相有很大的关系,合金的主要强化机制是沉淀强化。     

Cu含量对Zn20Sn无铅钎料腐蚀性能影响

采用合金化原理,在Zn20Sn钎料基体中添加不同含量铜,形成新型合金Zn20SnxCu,研究铜含量对Zn20SnxCu无铅钎料腐蚀性能影响. 结果表明,当铜添加量小于4%时,随着铜添加量的增加,Zn20SnxCu钎料合金的腐蚀电位逐渐升高,腐蚀速率逐渐降低,合金耐腐蚀性逐渐增强;当铜添加量大于4%时,随着铜添加量的增加,Zn20SnxCu钎料合金的腐蚀电位逐渐降低,腐蚀速率增加,耐腐蚀性下降. Zn20SnxCu腐蚀表面主要产物为Zn₅(OH)₈Cl₂·H₂O和ZnO. 从Zn20SnxCu腐蚀性能考虑,铜最佳添加量为4%.     

热挤压对铸态Mg-1Zn-0.3Zr-1Y-2Sn镁合金组织和性能的影响（英文）

通过光学显微镜(OM)、扫描电镜(SEM)、浸泡实验、析氢实验、电化学试验、拉伸试验等方法,研究了不同挤压温度(340、360、380、400℃)下,热挤压对铸态Mg-1Zn-0.3Zr-1Y-2Sn合金组织和性能的影响。结果表明:热挤压后,合金的第二相沿挤压方向破碎成颗粒,微观组织中存在动态再结晶和变形晶粒。随着挤压温度的升高,第二相的含量变化较小,动态再结晶晶粒尺寸逐渐增大。热挤压后,合金的力学性能得到改善,但其耐腐蚀性最终减弱。热挤压处理可以在腐蚀的早期阶段提高合金的耐腐蚀性能,但随着腐蚀的进行,在后期合金的耐蚀性能会降低。当热挤压温度为360℃时,合金具有较好的力学性能和耐腐蚀性能。     

快速凝固+热挤压制备Al-10.7Zn-2.4Mg-0.9Cu合金的组织和性能

采用单辊熔体旋转法制备Al-10.7Zn-2.4Mg-0.9Cu合金带材,利用热挤压将带材坯料制成棒材,对其微观组织和力学性能进行研究。结果表明:所制备的带材由过饱和固溶体α(Al)等轴细晶构成,晶粒尺寸为3~5μm;合金经挤压后存在粗大第二相,析出相主要为MgZn2相,挤压态棒材抗拉强度为499.8 MPa,伸长率达到了15.3%,断口呈韧性断裂特征;经T6热处理后,合金中有细小的沉淀相析出,使得室温力学性能得到提高,抗拉强度达到631.9 MPa,伸长率有所降低,断口呈韧脆混合断裂特征。     

Effects of Sr addition on microstructure,mechanical properties and in vitro degradation behavior of as-extruded Zn−Sr binary alloys

The microstructures, mechanical properties and in vitro degradation behavior of as-extruded pure Zn and Zn−xSr (x=0.1, 0.4, 0.8 wt.%) alloys were investigated systematically. For the microstructure and mechanical properties, SrZn₁₃ phase was newly formed due to the addition of 0.1 wt.% Sr, improving the yield strength, ultimate tensile strength and elongation from (85.33±2.86) MPa, (106.00±1.41) MPa and (15.37±0.57)% for pure Zn to (107.67±2.05) MPa, (115.67±2.52) MPa and (20.80±2.19)% for Zn−0.1Sr, respectively. However, further increase of Sr content led to the deterioration of the mechanical properties due to the stress concentration and cracks initiation caused by the coarsening SrZn₁₃ particles during tensile tests. For in vitro degradation, since micro galvanic corrosion was enhanced owing to the formation of the inhomogeneously distributed SrZn₁₃ phase, the corrosion mode became non-uniform. Corrosion rate is gradually increased with the addition of Sr, which is increased from (11.45±2.02) μm/a (a=year) for pure Zn to (32.59±3.40) μm/a for Zn−0.8Sr. To sum up, the as-extruded Zn−0.1Sr alloy exhibited the best combination of mechanical properties and degradation behavior.     

Microstructure,mechanical properties,and corrosion resistance of Mg–9Li–3Al–1.6Y alloy

Mg–9Li–3Al–1.6Y alloys were prepared through mixture method. The microstructure, mechanical properties, and corrosion resistance of the as-cast and asextruded alloys were studied by optical microscopy(OM),scanning electronic microscopy(SEM), X-ray diffraction(XRD), mechanical properties testing, and electrochemical measurement. The as-cast Mg–9Li–3Al–1.6Y alloy with the average grain size of 325 lm is composed of b-Li matrix, block a-Mg, and granule Al_2Y phases. After extrusion, the grain size of the as-cast alloy is obviously refined and reaches to 75 lm; the strength and elongation of the extruded alloy are enhanced by 17.20 % and49.45 %, respectively, owing to their fine microstructure and reduction of casting defects. The as-extruded alloy shows better corrosion resistance compared to the as-cast one, which may be related to the low stored energy and dislocation density in the extruded alloy, also the homogenization treatment before extrusion.