Zn对粉末冶金法制备Mg-Zn合金组织与性能的影响（英文）

以Mg粉和Zn粉为初始原料,采用粉末冶金技术制备Mg-Zn合金。研究了Zn含量对Mg-Zn合金烧结密度、显微组织、物相组成、弯曲强度和显微硬度的影响。测量了Mg-Zn合金的耐腐蚀性,探讨了Zn元素在粉末冶金过程中的作用机理。结果表明,添加Zn元素后,烧结产物的晶粒细小,烧结密度提高。此外,随着Zn含量的增加,烧结产物的致密度持续增加。XRD分析表明Mg-3%Zn(质量分数)合金主要由α-Mg相组成,而Mg-4%Zn合金由α-Mg和MgZn_2两相组成。随着Zn含量的增加,Mg-Zn合金的抗弯曲强度先增加而后降低,但是显微硬度(HV)持续增加。Mg-3%Zn合金的抗弯强度为123.6 MPa,显微硬度为1017 MPa,分别比纯Mg样品高出58%和45%。耐腐蚀性能测试表明当添加Zn元素后,Mg-Zn合金的腐蚀速率降低,Mg-3%Zn合金具有最低的腐蚀速率和最佳的耐腐蚀性能。     

Zn对粉末冶金法制备Mg-Zn合金组织与性能的影响

以Mg粉和Zn粉为初始原料,采用粉末冶金技术制备Mg-Zn合金。研究了Zn含量对Mg-Zn合金烧结密度、显微组织、物相组成、弯曲强度和显微硬度的影响。测量了Mg-Zn合金的耐腐蚀性,探讨了Zn元素在粉末冶金过程中的作用机理。研究结果表明当添加Zn元素后,烧结产物的晶粒细小,烧结密度提高。此外,随着Zn含量的增加,烧结产物的致密度持续增加。XRD分析表明Mg-3 wt%Zn合金主要由α-Mg相组成,而Mg-4 wt%Zn合金由α-Mg 和 MgZn₂两相组成。随着Zn含量的增加,Mg-Zn合金的弯曲强度先增加而后降低,但是显微硬度持续增加。Mg-3 wt% Zn合金的抗弯强度为123.6 MPa,显微硬度为101.7 HV,分别为纯Mg样品高出58%和45%。耐腐蚀性能测试表明当添加Zn元素后,Mg-Zn合金的腐蚀速率降低,Mg-3 wt%Zn合金具有最低的腐蚀速率和最佳的耐腐蚀性能。     

医用镁锌合金的制备及显微组织分析

选择人体必需元素Zn作为合金元素,制备了不同Zn含量的Mg-Zn合金,分析了Mg-Zn合金的显微组织。结果表明,合金由α-Mg固溶体和较少的Mg Zn相组成。随着Zn含量的增加,铸态Mg-Zn合金组织中的Mg Zn相含量增加,形态由点状逐渐转变为片状。     

Zn含量对Mg-xZn合金组织和力学性能的影响

制备了Mg-x Zn二元合金,研究了不同Zn含量对铸态Mg-x Zn(x=2,4,6,8,10和15,质量分数)合金显微组织和力学性能的影响。结果表明,合金组织主要由基体α-Mg和沿晶界分布的共晶相组成。随着Zn含量增加,共晶相的形态由颗粒状逐渐演变成完全连续的网状,晶粒尺寸得到细化;合金的抗拉强度和伸长率都呈先增加后减小的趋势。当Zn含量为4%时,合金的伸长率获得了最大值,为10.78%,而抗拉强度在Zn含量为6%时达到了210 MPa。Zn含量的逐渐增加使合金的断裂行为由准解理断裂向解理断裂转变。     

Zn元素对Mg-25Sn合金组织和力学性能的影响

以Mg粉、Sn粉和Zn粉为初始原料,采用机械合金化和热压烧结的方法制备Mg-25Sn-x Zn合金。研究了Zn添加量对Mg-25Sn合金显微组织和性能的影响。结果表明:Mg-25Sn-x Zn体系的机械合金化过程中,Zn元素不参与合金化反应,但Zn的引入降低了Mg+Mg2Sn混合物的尺寸。除固溶外,烧结态Mg-25Sn-x Zn中Zn完全转变成MgZn2相。且随Zn含量的增加,MgZn2相的尺寸逐步增大,Mg晶界和Mg2Sn颗粒相周围是MgZn2相的择优分布位置。添加6%Zn(质量分数)的Mg-25Sn合金具有最优的力学性能,其显微维氏硬度为1.60GPa、屈服强度为388MPa、抗压强度为497 MPa、断裂应变7.5%。     

Ca对铸态Mg-4Zn合金组织及腐蚀性能的影响

为开发生物医用镁合金,利用高纯原材料,在氩气气氛保护下熔炼浇铸制备了Ca合金化的Mg-4Zn合金(Ca含量分别为0.4%和1.0%,质量分数)。通过OM、SEM以及XRD分析了合金的微观组织和相组成,采用析氢法、腐蚀质量损失法以及电化学法测试了合金在Hanks模拟体液中的腐蚀行为。结果表明,合金由初生Mg固溶体和共晶体组成;随Ca含量增加,合金的电荷传递电阻减小,自腐蚀电位下降,自腐蚀电流密度增加;析氢法和腐蚀质量损失法均表明合金的腐蚀速率随时间延长而减小。共晶体对合金的耐蚀性有影响;当Ca含量从0.4%增加到1.0%时,共晶体含量增加,促进了合金的电偶腐蚀,合金耐蚀性降低。Mg-4Zn-(0.4,1)Ca合金的腐蚀形式主要为晶间腐蚀和点蚀。     

Mg-x％Zn-(Al)合金显微组织及力学性能

利用光学显微镜、X射线衍射仪、扫描电镜和万能力学试验机研究了Mg-x％Zn(5、7、9、15和20％)二元合金和Mg-7Zn-4Al合金的显微组织及力学性能.结果表明:Mg-Zn合金铸态显微组织主要由α-Mg和沿晶界分布的Mg7Zn3共晶相组成.随着Zn含量的增加,Mg-Zn二元合金的抗拉强度呈先上升后下降的趋势,而伸长率呈逐渐下降的趋势.当Zn含量为7％时,合金的抗拉强度达到最大,为213.3 MPa;当Zn含量高于9％后,合金的抗拉强度和伸长率急剧下降.在Mg-7Zn基体合金中添加4％Al后,合金的显微组织主要由oα-Mg和Mg32(Al,Zn)49三元共晶相组成.合金的铸态力学性能相对于基体有所下降,但是热处理后抗拉强度得到显著提高,为305 MPa,相对铸态提高了57.8％.Mg-Zn合金中添加A1元素有利于合金的热处理强化.     

不同钨精矿粉末含量对Fe-Al系激光自蔓延烧结合金组织性能的影响

通过对掺杂钨精矿粉末的Fe40Al60粉末压坯进行激光点燃自蔓延烧结,制备原位自生颗粒增强复合材料。利用表征手段分析钨精矿粉末添加量对烧结合金显微组织结构及宏观性能的影响规律。结果表明,随钨精矿粉含量的增加,合金显微组织由片状变为颗粒状,烧结合金物相主要为Al2O3、FeAl、Fe3Al、Fe7W6、W及硬质颗粒相WO3。当钨精矿粉末含量为1%时,烧结合金密度最大,为4.27 g/cm3;孔隙率最小,为12.2%;硬度最高,上表层区达到1050 HV,中部区达到1818 HV,底层区达到1232 HV;合金磨损率最低,表层区为0.99 mg/mm2,中部区为0.59 mg/mm2,底层区为0.75 mg/mm2;合金耐蚀性能最好,腐蚀电流密度为116μA/cm2。     

激光熔覆CoCrFeNiSix高熵合金涂层组织及耐蚀性能研究

目的 研究Si含量对CoCrFeNi系高熵合金涂层组织、物相、显微硬度及耐蚀性能的影响.方法 通过激光熔覆技术在45钢基材上制备CoCrFeNiSix(x为物质的量之比,x=0.0,0.5,1.0,1.5,2.0)高熵合金涂层,使用扫描电镜、X射线衍射仪、显微硬度仪、电化学工作站对涂层的显微组织、物相组成、显微硬度、耐蚀性能、腐蚀形貌进行分析研究.结果 CoCrFeNi高熵合金涂层为单一的fcc相,之后随着Si含量的提升,涂层向bcc相转变,当x=2.0时,全部转化为bcc相.涂层的微观组织以等轴晶与枝晶为主,当Si含量较少时,Si元素主要在晶界中偏析,随着Si含量的增加,过多的Si会固溶到晶粒内部.涂层的平均显微硬度随着Si含量的升高而增加,CoCrFeNiSi2.0可达到566.5HV0.5.在3.5％NaCl溶液中,涂层的腐蚀电位随Si含量的增加而变大,CoCrFeNiSi2.0较CoCrFeNiSi0.0的腐蚀电位正移约160 mV,腐蚀电流密度从1.17×10-6 A/cm2减小到6.06×10-7 A/cm2,耐蚀性提高.当Si含量较低时,涂层表面出现连续大面积腐蚀痕迹,随着Si含量的增加,表面腐蚀以点蚀为主.结论 在CoCrFeNi系高熵合金涂层中添加Si元素,可以促进bcc相的生成,提高涂层的显微硬度,同时可以有效抑制合金涂层的腐蚀倾向,以及减缓合金涂层的腐蚀速率,提高耐蚀性能.     

时效处理对医用镁锌合金微观组织的影响

对不同Zn含量的Mg-Zn合金进行时效处理,研究时效处理对Mg-Zn合金显微组织的影响。结果表明,Mg-Zn合金时效处理后,Zn从Mg基体中脱溶出来,以MgZn相的形式存在。Mg-Zn合金时效处理后,随着Zn含量增加,第二相沿晶界由片状分布向网状分布转变。     

固溶处理对Mg-3Gd-1Zn合金在模拟体液中腐蚀性能的影响

目的探究固溶处理对Mg-3Gd-1Zn生物镁合金腐蚀性能的影响规律。方法对Mg-3Gd-1Zn镁合金进行不同温度的固溶处理,随后进行时效处理。采用扫描电镜(SEM)对合金的显微组织进行观察,利用失重法和析氢法测试合金在模拟体液(SBF)中的腐蚀性能,利用极化曲线和交流阻抗谱对合金的电化学行为进行评估。结果由失重法计算结果可知,T6-460、T6-510、T6-520和T6-530合金在SBF中浸泡120h后的腐蚀速率分别为2.48、1.19、0.86、1.17 mm/a,即随着固溶温度的增加,合金的腐蚀速率顺序为:T6-460T6-510T6-530T6-520。析氢测试结果表明,随着浸泡时间的增加,T6-460与T6-510合金的腐蚀速率升高,而T6-520与T6-530合金的腐蚀速率变化较小,浸泡120 h后的析氢分析结果与失重法计算结果趋势一致。电化学测试表明,T6-460、T6-510、T6-520和T6-530合金的电流密度分别为8.01×10~(-5)、3.85×10~(-5)、3.30×10~(-5)、3.90×10~(-5)A/cm~2。随着固溶温度的增加,合金的容抗弧半径先增加后减小。合金在腐蚀过程中发生了点蚀。结论四种测试方法均表明T6-520镁合金表现出最佳的耐蚀性。     

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.     

Gd添加量对Zn-1.2Cu-1.2Mg锌合金组织和性能的影响

研究了Zn-1.2Cu-1.2Mg-xGd（x=0,0.1,0.25,0.5,质量分数,%）锌合金微观组织、在模拟体液中的腐蚀行为和力学性能。结果表明,锌合金组织主要由Zn固溶体和Mg₂Zn₁₁金属间化合物组成。当Gd添加量为0.5%时,形成了GdZn₁₂化合物。锌合金的硬度随Gd添加量的增加而增加,在0.5% Gd添加量时,硬度达到最大值为1530 MPa。在0.25% Gd添加量时锌合金具有高的抗拉伸强度,而在0.1% Gd添加量时锌合金具有最低的腐蚀速率。     

Mg-Nd-Gd-Zn-Zr镁合金铸造组织与力学性能

采用正交试验方法,通过砂型铸造制备9种不同成分的Mg-Nd-Gd-Zn-Zr系镁合金。研究该系列镁合金的铸造组织和室温力学性能,并通过对力学性能试验数据的分析,研究主要合金化稀土元素Gd和Nd的作用。研究发现:该系列镁合金铸态组织为α-Mg基体和Mg12Nd化合物。经过固溶处理后,铸态组织中晶界上的化合物大部分溶入基体,但在晶界上还有一些颗粒状的化合物。Gd含量越高,合金的室温抗拉强度、屈服强度和延伸率就越高。Nd含量越高,抗拉强度和屈服强度也越好,但延伸率在Nd含量超过2水平(2.85%)后会降低。抗拉强度和屈服强度受Nd含量的影响最大,Gd含量的影响次之。Zn含量越高屈服强度越高,但抗拉强度和延伸率降低,其中延伸率受Zn含量的影响最大。     

Mechanical properties,corrosion behavior,and microstructure of Sr modified Al–9.2Mg–0.7Mn alloys

The influence of strontium (Sr) additions in the form of Mg–Sr master alloys from 0 to 0.6 wt% on the mechanical properties, corrosive nature, and microstructure of Al–9.2Mg–0.7Mn alloys is investigated. The material is studied in a fully annealed (O‐temper) and a sensitizing treatment at 150°C for 7 days. Here we demonstrate that there will be a new phase which might be (Al, Mg)₁₇Sr₂ formed in the as‐cast microstructure. When the Sr content is 0.2 wt%, under the premise that the mechanical properties of completely annealed alloy change little (relative to the matrix: the ultimate tensile strength increases by 8 MPa and the elongation only decrease by 1.6%), the intergranular corrosion resistance is significantly improved. The specific performance is that the mass loss from intergranular corrosion decreases by more than 53% from the addition of 0.2 wt% Sr after sensitizing.     

Effect of Zn on mechanical property and corrosion property of extruded Mg-Zn-Mn alloy

The effect of Zn on the microstructure, the mechanical property and the corrosion property in simulated body fluid（SBF） of an extruded Mg-Mn alloy was studied. The results indicate that the addition of Zn element can significantly refine the grain size of the extruded Mg-Mn alloy. When Zn content is increased from 0% to 3%, the grain size decreases from 12μm to 4 p.m. Meanwhile, the mechanical properties also increase remarkably with increasing Zn content. When Zn content is 3%, the ultimate tensile strength and the yield strength are increased by 54.7 MPa and 69.7 MPa, respectively. Zn can also improve the anti-corrosion property of the alloy. The best anti-corrosion property is obtained with 1% Zn. However, further increase of Zn content up to 3% deteriorates the corrosion property. Finally, the influence mechanism of Zn on the microstructure, the mechanical property and the corrosion property was discussed.     

YbB6 对Ti-6Al-4V钛合金组织和性能的影响

采用放电等离子烧结（SPS）制备了含YbB₆的Ti-6Al-4V钛合金,并研究了YbB₆对Ti-6Al-4V钛合金显微组织和力学性能的影响。结果表明,随着YbB₆含量的增加,复合材料的显微组织发生转变,晶粒明显细化,原位反应生成的TiB晶须和Yb₂O₃颗粒有利于复合材料力学性能的提高。此外,当添加0.6%（质量分数）YbB₆后,烧结样品的相对密度、显微硬度、屈服强度、极限拉伸强度和延伸率分别为99.43%、4030 MPa、903 MPa、1148 MPa和3.3%。与Ti-6Al-4V试样相比,其数值分别提高了0.37%、13.8%、38.07%和17.14%。强化机制主要是组织转变、晶粒细化和弥散强化。随着YbB₆含量的增加,断裂方式主要为韧性断裂和脆性断裂。     

Effect of Mo and Y2O3 additions on the microstructure and properties of fine WC-Co cemented carbides fabricated by spark plasma sintering

The effects of Mo and Y₂O₃ additions on the microstructure and properties of fine WC-6Co cemented carbides prepared by spark plasma sintering (SPS) were investigated. The microstructure, mechanical properties and corrosion behavior were analyzed by SEM, TEM, XPS, mechanical property tests and potentiodynamic polarization curve measurements. The results show that there are no significant differences in the microstructure and properties of alloys with 1.0% Y₂O₃ addition. However, the addition of Mo was beneficial for refining the WC grains. The hardness of alloys increased until the maximum value, and then followed a decreasing trend with the increase of Mo content. In addition, the relative density of alloys decreased with the increase of Mo addition, which caused to an obvious decline in fracture toughness. With the additions of Mo and Y₂O₃, the corrosion resistance of alloys improved significantly both in acid and alkaline solutions (0.1 M HCl and 0.1 M NaOH solutions). The adding amount of Mo should be controlled within a certain range and 1 wt% of Mo has the most positive effect on the comprehensive properties of WC-6Co alloys.     

SVET study of the corrosion protection of electrodeposited Zn and Zn‐Co‐Fe alloy coated steels

The scanning vibrating electrode technique (SVET) was applied to study the corrosion resistance of partially coated (Zn and various Zn‐Co‐Fe alloys) and partially exposed steel samples in 10 mM NaCl solution. The sacrificial properties and the protection range decreases with increase in Co content in the alloy. For high Co content in the alloy, the coating becomes more noble to steel and loses its sacrificial protection. The barrier resistance of the coatings increases with the increase in Co content in the alloy coating. Zn‐Co‐Fe alloys with high Co content (i.e., 32 wt% Co and 1 wt% Fe) showed excellent barrier properties due to passivation after dezincification protecting the underlying steel. An intermediate region of compositions can be distinguished in which the coatings provide a good combination of sacrificial and barrier resistance properties and also a reasonable protection range.