Characterization of the Ti-10Nb-10Zr-5Ta Alloy for Biomedical Applications. Part 1: Microstructure, Mechanical Properties, and Corrosion Resistance

Ti-10Nb-10Zr-5Ta alloy was investigated as possible material candidate for replacing Ti6Al4V in medical applications. The alloy was prepared in a levitation melting furnace and characterized in terms of elemental and phase composition, microstructure, mechanical properties, and corrosion resistance in simulated body fluid and Fusayama Meyer artificial saliva solutions. The characteristics of the new alloy were compared to those of the Ti6Al4V alloy. The Ti-10Nb-10Zr-5Ta system was found to posses of a polyhedral structure consisting in α′ and β phases. X-ray structural analysis revealed a mixture of hexagonal α′ martensite (main phase, with grain size of about 21 nm) and β bcc phase. The Ti-10Nb-10Zr-5Ta alloy exhibited some better mechanical properties (Young modulus, tensile properties) and corrosion resistance (polarization resistance, corrosion current density, and corrosion rate), as compared to Ti6Al4V alloy.     

热机械处理对Ti-45Al-5Nb-0.3Y合金的显微组织与力学性能的影响

包套锻造Ti-45Al-5Nb-0.3Y合金由大量细小的动态再结晶等轴γ晶粒(晶粒尺寸可达1-2 μm),弯曲或破碎的层片和少量的残余平直层片组成,变形组织含有人量位错及少量变形孪晶.锻态试样抗拉强度(σb),延伸率(δ)分别达到708.1 MPa和0.95%.再通过不同的热处理分别得到晶粒细小的双态组织、近层片组织和全层片组织.经1320 ℃/30 min炉冷后得到双态组织,层片晶粒尺寸(d1)约为20 μm,层片体积分数(ψ1)约为60%,具有最高的δ,约为1-9%,σb约为658.9 MPa,为穿晶和沿晶混合断裂;经1340℃/30 min炉冷后得到近层片组织,dI约为60 gm,ψ1约为95%,O'b约为690.2 MPa,δ约为1.75%,上要为穿晶(层片)断裂;经1370℃/15 min炉冷后得到细小全层片组织(d1约为40 μm),具有最高的σb,约为715.1 MPa,5约为1.51%,为穿晶断裂.     

放电等离子烧结温度对Ti-35Nb-7Zr-5Ta合金显微组织和力学性能的影响

利用放电等离子烧结技术(SPS)制备了Ti-35Nb-7Zr-5Ta合金,研究了烧结温度对合金致密度、显微组织及力学性能的影响。结果表明:在950~1150℃烧结温度范围内合金主要由β-Ti相和Ti-Nb-Ta-Zr固溶体组成的混合基体及少量未熔化的Nb、Ta金属颗粒组成,并且合金具有较高的致密度和抗压强度;随着烧结温度的升高,合金中混合基体组织尺寸越来越大且不断融合联结,Nb、Ta金属颗粒数量越来越少且尺寸越来越小,同时合金致密度和抗压强度呈增大趋势;所制备的合金压缩弹性模量值在50~57 GPa之间,具有良好的力学相容性,烧结温度变化对其影响较小。     

Microstructure and mechanical behavior of a Ti-24Nb-4Zr-8Sn alloy processed by warm swaging and warm rolling

A combination processing technique of warm swaging and warm rolling is proposed to refine grains and improve the mechanical properties of a multifunctional β-type Ti-24Nb-4Zr-8Sn (wt.%) alloy. The results show that a highly swirled marble-like microstructure can be easily produced by warm swaging at an initial temperature of 573 K, whereas it has little effect on the nonlinear elastic deformation compared with the hot forged alloy with an equiaxed microstructure. Although the swirled microstructure has the limitation of an inhomogeneous distribution, swaging has the great advantage of refining the initial subgrains produced by hot forging with little loss of ductility. The following warm rolling at an initial temperature of 673 K results in a uniform microstructure comprising β phase with a size less than ∼200 nm and the precipitation of nanosized α phase. Therefore, significant grain refinement was achieved through the formation and refinement of the subgrains. The ultrafine grained alloy exhibits large scale nonlinear deformation behavior with a recoverable strain of up to ∼3.4% in combination with a high strength of ∼1150 MPa, a low elastic modulus of ∼56 GPa and good ductility of ∼8%. Such an improvement in mechanical properties indicate great potential for biomedical applications.     

Characterization of the Ti-10Nb-10Zr-5Ta Alloy for Biomedical Applications. Part 2: Wettability, Tribological Performance and Biocompatibility

The Ti-10Nb-10Zr-5Ta alloy, prepared in a levitation melting furnace, was investigated as a possible candidate for replacing Ti6Al4V alloy in medical applications. The sessile drop method, pin-on-disc and in vitro tests were used to analyze wettability, wear resistance, and biocompatibility of the new alloy. The characteristics of the Ti-10Nb-10Zr-5Ta alloy were assessed in comparison to those of the Ti6Al4V alloy. The Ti-10Nb-10Zr-5Ta system was found to have hydrophilic characteristics with similar contact angle as the Ti6Al4V alloy. In all environments (deionized water, simulated body fluid and Fusayama Meyer artificial saliva), the friction coefficient showed a stable evolution versus sliding distance, being similar for both alloys. On overall, the wear resistance of Ti-10Nb-10Zr-5Ta alloy was lower than that of Ti6Al4V for all testing environments. The Ti-10Nb-10Zr-5Ta alloy exhibited good biocompatibility characteristics at in vitro test compared to Ti6Al4V alloy. The cell viability on Ti-10Nb-10Zr-5Ta surfaces was higher than the one observed on Ti6Al4V samples, regardless the number of days spent in osteoblast-like cells culture. A high degree of cell attachment and spreading was observed on both alloys.     

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。     

20Zr-70Ti-6Al-4V合金静动态力学性能研究

以20Zr-70Ti-6Al-4V合金为研究对象,采用XRD、DSC、OM和SEM等测试分析技术,研究了合金在退火处理和固溶时效处理过程中的相变及组织演化规律,并通过万能试验机和分离式霍普金森压杆,进一步研究了组织与应变速率对合金静动态力学性能的影响。结果表明:20Zr-70Ti-6Al-4V合金经退火和固溶时效后均由α相和β相组成,呈现为网篮组织,在静态加载条件下,抗拉强度最高可达1301 MPa,塑性应变最高可达14.9%,抗压强度最高可达1386MPa,断裂方式为韧性断裂;在动态加载条件下,应变速率处于1000到3000 s~(-1)这一高应变率范围时,20Zr合金的动态抗压强度有明显提高,表现为应变率强化效应,在同一应变速率下,20Zr合金固溶时效态的抗压强度和失效应变均高于退火态;动态压缩试样表面观测到与压缩轴呈45°角的宏观裂纹,动态破坏模式为绝热剪切失稳破坏。     

时效温度对Ti-5Al-4Zr-10Mo-3Cr钛合金微观组织及力学性能的影响

研究了Ti-5Al-4Zr-10Mo-3Cr合金经过β相区固溶(880 ℃)、不同温度时效(540~620 ℃)处理后次生α相(α_s)析出形貌及其对力学性能的影响。结果表明:随着时效温度由540 ℃升高至620 ℃,合金中析出α_s相片层厚度由0.030 μm增加到0.142 μm,屈服强度由1353 MPa降低至1074 MPa,断后伸长率由2.5%升高至11.4%,即时效析出的微米级片层α_s能够显著调控合金的力学性能。此外,时效温度升高使合金的拉伸断裂由沿晶脆性断裂为主转变为韧窝穿晶为主的韧性断裂方式。Ti-5Al-4Zr-10Mo-3Cr合金时效析出的片层状α_s相的厚度大于0.1 μm,合金的断后伸长率≥6%。当时效温度为600 ℃时,合金的硬度为387 HV10,抗拉强度为1182 MPa,伸长率为8.5%,具有良好的强塑性匹配。     

Ti-22Al-24Nb-0.5Mo电子束焊接接头组织性能研究

对Ti-22Al-24Nb-0.5Mo合金的电子束焊接接头开展研究,焊接接头熔合区由B₂相柱状晶和分布在上下边缘的少量枝状晶组成,并且沿中心轴对称分布。对焊接接头进行了850_oC/2hr/AC(时效)与980_oC/2hr+850_oC/24hr/AC(固溶+时效)两种热处理,时效态接头熔合区的B₂相中析出了大量针状O相,而固溶+时效态熔合区的O相更为粗大,且α₂相重新形成。两种热处理后接头的常温拉伸性能相近,但在高温下时效态接头的强度稍高。固溶+时效态接头的650_oC持久寿命高于时效态,失效模式都为沿晶断裂。     

放电等离子烧结技术制备(Ti-35Nb-7Zr-5Ta)-15HA复合材料微观组织的演变及生物活性

为了提高生物材料的生物活性并降低弹性模量,利用放电等离子烧结技术制备(Ti-35Nb-7Zr-5Ta)-15HA生物复合材料,研究不同烧结温度(950～1150℃)对复合材料相对密度、微观组织演变、力学性能及生物活性的影响。结果表明:随着温度的升高,复合材料相对密度从87.6%提高到97.5%;复合材料主要由β-Ti相、α-Ti相及陶瓷相,如Ti₂O、CaZrO₃、CaO、Ti₅P₃和Ca₃(PO₄)₂等组成;复合材料的弹性模量为30～95 GPa、抗压强度为593～1978MPa,而且随着烧结温度升高呈增大趋势;同时,在模拟体液中浸泡14d后,复合材料表面能够获得类骨磷灰石,显示出良好的生物活性,但随着温度的升高,类骨磷灰石含量不断减少。因此,950℃下烧结的(Ti-35Nb-7Zr-5Ta)-15HA生物复合材料是潜在的良好的生物植入材料。     

热暴露对Ti-44Al-4Nb-4Zr-0.2Si-1B合金显微结构及力学性能的影响

采用扫描电镜、透射电镜以及拉伸和高周疲劳等试验手段研究10 000 h、700℃大气热暴露过程对Ti-44Al-4Nb-4Zr-0.2Si- 1B合金显微结构和力学性能的影响.结果表明:复合含Nb-Zr的TiAl合金的α2+γ层片组织显示出较高的热力学稳定性,合金的α2+γ层片晶团在热暴露过程中,α2→γ和α2+γ→B...     

基于CMT的电弧熔丝增材Ti-6Al-3Nb-2Zr-1Mo合金的组织与性能

采用基于冷金属过渡的电弧熔丝增材方法(CMT-WAAM)制备了Ti-6Al-3Nb-2Zr-1Mo合金试样,研究了CMT-WAAM Ti6321合金显微组织、力学性能及其各向异性. 结果表明,CMT-WAAM Ti6321合金显微组织由不规则的多边形原始β晶和晶界α相组成,CMT脉冲工艺(CMT+P)能够有效细化晶粒,组织中没有发现贯穿式的柱状晶,且未发现马氏体.CMT-WAAM Ti6321合金x向和z向的室温抗拉强度达到同级别锻件标准,断口形式均为典型的韧性断裂.成形组织中没有明显的织构存在,拉伸强度的各向异性也不明显,组织中的气孔导致z向的断后伸长率低与x向. x向和z向冲击韧性均不低于65 J,能够满足船用钛合金结构件的需求,冲击断口中存在大量的撕裂型韧窝,为典型的韧性断裂.     

固溶温度对SPS烧结Ti-24Nb-4Zr-8Sn合金组织和力学性能的影响

利用放电等离子烧结技术(SPS)制备了生物医用Ti-24Nb-4Zr-8Sn合金,研究了固溶温度对合金显微组织和力学性能的影响。结果表明：合金在相变点下(750 ℃)固溶后,显微组织主要由β相、初生α相和次生α相组成,当固溶温度升至相变点附近(775 ℃)时,β晶粒尺寸显著增大,晶界初生α相厚度和数量均明显减小,β晶粒上弥散分布着大量细针状与颗粒状的次生α相;随着固溶温度的进一步升高,晶界α相厚度和数量减小并逐渐连续呈网状,β晶粒内部次生α相不均匀析出且数量逐渐减少;与烧结态相比,合金强度和弹性模量随固溶温度的提高呈先升高后降低趋势,而塑韧性逐渐提高。     

Ti-7.5Nb-4Mo-2Sn-1.6Si合金的显微组织及超弹性行为

采用真空电弧熔炼法制备Ti-7.5Nb-4Mo-2Sn-1.6Si（原子百分比,at%）合金,在800 ℃对合金进行了热压处理（变形量为50%）, 然后在700 ℃对合金进行固溶处理20 min,对其显微组织和超弹性性能进行了研究。该合金显微组织由b相和少量a″相组成,在b相基体中有弥散细小的Ti₅Si₃颗粒的析出。与Ti-7.5Nb-4Mo-2Sn合金相比,由于Si的固溶强化和Ti₅Si₃的弥散强化作用,含1.6at%合金的应力诱发马氏体相变临界应力得到提高,从而使该合金在室温下表现出更好的超弹性。随着预变形量的增加,该合金的超弹性回复率降低。在预变性量为4%条件下,对该合金进行循环拉伸-卸载“训练”,在经过11次循环后,合金的超弹性得到进一步改善。     

Microstructure,mechanical properties,and corrosion resistance of Ti-20Zr alloy in undoped and NaF doped artificial saliva

The corrosion behavior of a new, advanced Ti-20Zr alloy with α+β microstructure (determined by optical microscopy, XRD, and SEM) and very good mechanical properties (obtained from the stress-strain curve) is studied in this paper. The composition of the alloy native passive film was determined from a XPS analysis and the long-term corrosion resistance in undoped and doped states with 0.05M NaF artificial Carter-Brugirard saliva of different pH values, simulating the severe functional conditions of a dental implant, was analyzed by electrochemical methods. This alloy possesses an advantageous balance between good mechanical resistance and plasticity and Young’s modulus and exhibits more favorable electrochemical parameters and corrosion resistance than CP Ti due to its more resistant passive layer containing Ti₂O₃, TiO₂, and ZrO₂ protective oxides. After 1000 h of immersion in saliva, the protective properties of the alloy were enhanced due to the deposited surface layer that incorporated protective phosphates (shown by SEM and XPS).     

快速凝固Cu-5Ag-0.5Zr-0.4Cr-0.35Nb合金的组织与力学性能

采用快速凝固方法制备了Cu-5Ag-0.5Zr及Cu-5Ag-0.5Zr-0.4Cr-0.35Nb(wt%)合金粉末,采用热等静压将粉末压制成坯料,随后进行热锻、冷轧处理。测试了合金在室温及高温(500 ℃)下的力学性能,并分析了合金的显微组织及断口形貌。结果表明,冷轧态合金具有更优异的室温拉伸性能,冷轧态Cu-Ag-Zr合金抗拉强度为739.3 MPa,伸长率7.1%,这与铜基体中密集的Cu₄AgZr颗粒及纳米级Ag颗粒有关。除Cu₄AgZr颗粒及Ag颗粒外,Cr、Nb元素的添加还生成高温稳定的Cr₂Nb颗粒,同时提高了合金的室温和500 ℃拉伸强度。冷轧态Cu-Ag-Zr-Cr-Nb合金的室温极限抗拉强度和伸长率分别为799.1 MPa与5.3%。因为热锻态合金晶粒尺寸粗大,Ag颗粒尺寸细小,相比冷轧态合金拥有更好的抗高温弱化性能。热锻态Cu-Ag-Zr-Cr-Nb和Cu-Ag-Zr合金的500 ℃抗拉强度分别为186.8和129.2 MPa,而冷轧态Cu-Ag-Zr-Cr-Nb和Cu-Ag-Zr合金在500 ℃抗拉强度分别仅为113.1和95.4 MPa。     

基于BP网络Ti-6Al-3Nb-2Zr-1Mo合金等温压缩流变应力预测

通过对Ti-6Al-3Nb-2Zr-1Mo合金820~970℃,0.001~1 s~(-1)条件下的热模拟压缩试验,得到不同变形条件下的高温变形真应力-真应变曲线。基于此实验数据建立了该合金BP-ANN本构预测模型和传统的回归模型。结果表明:2个模型的最大相对误差分别为4.35%和13.9%,平均绝对误差AARE分别为1.42%和6.53%,说明BP-ANN模型具有较优异的预测能力,此模型可作为Ti-6Al-3Nb-2Zr-1Mo钛合金高温变形本构模型。     

Ti-35Nb-7Zr-10CPP生物复合材料的微观组织演变与力学性能研究

利用放电等离子烧结技术制备了Ti-35Nb-7Zr-10CPP生物复合材料,研究了不同烧结温度(950~1150℃)对复合材料致密度、微观组织演变与力学性能的影响及机理。结果表明,复合材料主要由β-Ti相基体、少量残留α-Ti相及CaTiO_3、Ti_2O、CaO、CaZrO_3、Ti_xP_y等金属-陶瓷相组成;随着烧结温度升高,复合材料中残留α-Ti相逐渐减少,而金属-陶瓷相逐渐增多;复合材料的压缩弹性模量与抗压强度随烧结温度升高呈增大趋势,但是当烧结温度超过1050℃时,由于金属与陶瓷的剧烈反应导致金属-陶瓷相迅速增多,从而使得压缩弹性模量快速增大。因此,当烧结温度在1000~1050℃范围时,复合材料获得了较好的综合力学性能,其压缩弹性模量为42~45 GPa、抗压强度为1240~1330MPa;同时,在模拟人工体液中浸泡7 d后,复合材料表面能够获得一层致密的类骨磷灰石层,显示了良好的生物活性。     

不同SPS烧结温度Ti-45Al-5.5(Cr,Nb,B,Ta)合金的显微组织及力学性能(英文)

采用高能球磨和放电等离子烧结(SPS)技术,制备成分为Ti-45Al-5.5(Cr,Nb,B,Ta)的TiAl合金块体,随后对TiAl合金进行热处理。研究在不同SPS烧结温度下制备的TiAl合金经过热处理后的显微组织和力学性能。结果表明:高能球磨后的合金粉末形状不规则,粉末颗粒尺寸大约为几十微米。XRD分析表明,机械球磨后的粉末由TiAl和Ti3Al两相组成;烧结后的Ti-45Al-5.5(Cr,Nb,B,Ta)合金块体主要是TiAl相,以及少量的Ti3Al和TiB2相。当烧结温度为900°C和1000°C时,合金的显微组织为双相结构,并伴随有一些细小的等轴γ晶粒和细小的针状TiB2相。当烧结温度从900°C上升到1000°C时,Ti-45Al-5.5(Cr,Nb,B,Ta)合金的显微硬度变化不大,抗压强度从1812MPa提高到2275MPa,压缩率从22.66%增加到25.59%,合金的断裂方式为穿晶断裂。