摘要
通过多道次搅拌摩擦加工(MP-FSP)制备了医用可降解β-TCP/WE43复合材料,通过金相、扫描电子显微镜和能谱分析对β-TCP/WE43复合材料的显微组织进行了表征,并对该复合材料的力学性能、耐蚀性能和腐蚀摩擦磨损性能进行了测试分析.研究结果表明,在三道次搅拌摩擦加工后,β-TCP颗粒在镁基体中分散性较好,且搅拌区晶粒细小.多道次搅拌摩擦加工可以有效改善β-TCP颗粒在镁基体内的分布和细化晶粒,从而同时提高复合材料的机械性能、耐蚀性能和耐腐蚀磨损性能.该研究结果可为生物降解的镁基植入物的开发提供重要指导.
生物医用材料是用于诊断、治疗、修复或替换人体组织、器官或增进其功能的新型高技术材料,是医疗器械创新发展的“源头活水
控制镁植入物在体内的力学性能和降解速率是发展镁基生物可降解植入物的关键问题.目前,可以通过添加合金元素、表面涂层、使用热机械工艺使微观结构改性、添加生物陶瓷粉末形成镁基复合材料等方法解决这些问题.其中,通过添加生物陶瓷颗粒[如羟基磷灰石(HA)、β-磷酸三钙(β-TCP)]制备金属基复合材料是一种很有前景的方
镁基复合材料的制备工艺对其力学性能和耐腐蚀性也有重要影响.生物活性陶瓷加入镁基体中,采用剧烈塑性变形工艺,可以提高材料的力学性能、生物降解性能和生物活性.目前,人们常用的制备生物镁基复合材料方法有粉末冶金(PM)、火花等离子烧结(SPS)、搅拌铸造(SC)、熔体崩解沉积(DMD)、增材制造(AM)、搅拌摩擦加工(FSP)、等通道角挤压(ECAP)、高剪切凝固(HSS)等.Huang
WE43合金由4%的钇和3%的稀土元素组成,是一种典型的高强度稀土镁合金,引起了生物医学工程领域的极大兴趣.WE43的高强度和生物相容性使其适用于骨科植入物,如骨板、螺钉和销钉.β-TCP可以生物降解,是天然骨的成分,且具有良好的生物相容性,可以促进骨细胞的黏附和增殖,广泛应用于骨移植(如骨填充和骨置换)和仿生涂层材料.将β-TCP加入WE43合金中可以显著提升植入物的生物相容性.综上所述,搅拌摩擦加工技术制备的β-TCP/WE43复合材料是一种很有前景的生物植入物.本研究旨在通过多道次FSP方法制备高性能可降解的β-TCP/WE43稀土镁合金基复合材料,并研究FSP道次对β-TCP/WE43复合材料显微组织演变、力学性能、腐蚀性能和耐磨损性能的影响及潜在机理.
1 试验材料与方法
1.1 合金制备
本研究中采用成分为Mg-3.3Y-2.0Nd-1.3Gd-0.4Zr(质量百分数)的铸态WE43稀土镁合金,合金板厚度为10 mm.试验中采用球状的β-磷酸三钙 (β-TCP)活性陶瓷颗粒作为增强颗粒.采用搅拌摩擦加工技术在WE43合金板材表面加工一个宽为 1 mm、深为3 mm的凹槽用来填充β-TCP颗粒,加入β-TCP颗粒的体积百分数为12.5%.颗粒填充完毕后,使用无销的直圆柱形搅拌工具进行两道次封口处理,以防止增强颗粒在FSP过程中扩散.最后,使用带销的搅拌工具沿着凹槽进行搅拌摩擦加工,形成β-TCP/WE43复合材料.FSP中搅拌工具的旋转速度为1 500 r/min,行进速度为60 mm/min,进行单道次、双道次和三道次加工,以改善β-TCP颗粒在WE43基体内的分散状态.
1.2 微观组织表征
采用光学显微镜(4XCE, Shanghai Caikang Optical Instruments Co.,Ltd., China)、扫描电镜(SEM, FEI Quanta-200) 和能谱仪(EDS)对其微观结构进行表征.金相样品用腐蚀性溶液(4.2 g苦味酸,10 mL 乙酸,10 mL 水和 100 mL 无水乙醇)蚀刻10 s,取样位置是FSP后复合材料截面内的焊合区.
1.3 力学性能测试
在FSP 加工试样截面施加1.96 N载荷15 s,保压时间为 10 s,相邻测试点间隔0.5 mm,进行维氏显微硬度测量.拉伸试验的取样位置为搅拌区的中心区域,沿加工方向切割拉伸样,拉伸试样的形状和尺寸如

图1 拉伸试样尺寸示意图(单位:mm)
Fig.1 Tensile specimen size schematic diagram (unit: mm)
1.4 腐蚀行为测试
在室温的模拟体液(SBF溶液)中,通过电化学工作站(CHI-660C, CH Instruments Inc., China)进行了电化学测试.SBF溶液的组成为142 mmol/L N
通过测量样品在37 ℃ 的SBF中浸泡48 h后的失重来研究样品的降解行为.腐蚀试样为复合材料截面焊合区的长方体,尺寸为4 mm×3 mm×7 mm,浸入试样表面积(c
(1) |
式中:K 为常数,值为 8.76×1
1.5 磨损行为测试
使用SFT-2M型球盘式摩擦磨损试验仪进行磨损试验.磨损试验分别在空气(AIR)和SBF条件下进行,对磨材料为GCr15钢球(硬度为60 HRC).在磨损试验过程中,使用力传感器实时记录摩擦系数(COF).磨损试验在2 N、2.5 N、3 N、3.5 N载荷下进行40 min,转速为200 r/min,旋转半径为1 mm.通过接触式触针轮廓仪测量磨损轨迹的横截面,并根据磨损轨迹的横截面积计算磨损体积,磨损率ω由
(2) |
式中:V为磨损体积(m
2 结果分析
2.1 微观分析

图2 多道次搅拌摩擦加工制备的β-TCP/WE43复合材料的宏观形貌和微观组织
Fig.2 Macroscopic morphology and microstructure of the β-TCP/WE43 composites through multi-pass friction stir processing
(a) 截面宏观形貌;(b) 单道次;(c) 双道次;(d) 三道次
MP-FSP通过诱导剧烈的塑性变形破坏原有组织,形成大量的低角度晶界和取向错误的亚晶以及有利于成核再结晶的部位.低角度晶界通过持续动态再结晶(CDRX)转变为高角度晶界,之后细核发育为完美晶粒,形成细晶组织.β-TCP颗粒在复合材料晶粒细化机制中的作用归因于:1)β-TCP颗粒的钉扎作用,阻碍动态再结晶后晶粒的生长,从而使晶粒尺寸减小;2)β-TCP颗粒在再结晶过程中促进形核.金属基体中夹杂物使再结晶晶粒成核和抑制晶粒长大的基本原理已经确

图3 WE43合金和多道次搅拌摩擦加工制备的β-TCP/WE43复合材料的EDS元素能谱图
Fig.3 EDS elemental mappings of the WE43 alloy and the β-TCP/WE43 composites through multi-pass friction stir processing
(a) WE43 (b) 单道次β-TCP/WE43 (c) 双道次β-TCP/WE43 (d) 三道次β-TCP/WE43
2.2 力学性能分析
对多道次FSP制备的β-TCP/WE43复合材料的硬度和拉伸性能进行了分析,结果分别见
样品 | 屈服强度/MPa | 极限抗拉强度/MPa | 伸长率/% |
---|---|---|---|
单道次 | 217.1 | 218.9 | 4.05 |
双道次 | 233.3 | 250.9 | 4.58 |
三道次 | 233.5 | 237.9 | 4.90 |

(a) 硬度分布曲线

(b) 工程拉应力-应变曲线
图4 多道次搅拌摩擦加工制备的β-TCP/WE43复合材料的力学性能
Fig.4 Mechanical properties of the β-TCP/WE43 composites through multi-pass friction stir processing
搅拌摩擦加工后复合材料力学性能的提升取决于晶粒细化和增强颗粒在镁基体中的分散程度,其潜在机理是:1)搅拌摩擦加工后发生动态再结晶,产生细小的晶粒,引起细晶强化,可以通过Hall-Petch关系来确
2.3 腐蚀行为分析
WE43合金和三道次搅拌摩擦加工制备的β-TCP/WE43复合材料的动电位极化曲线如
样品 | Ecorr/V | Icorr/(A·c |
---|---|---|
WE43 | -1.86 |
4.998×1 |
β-TCP/WE43 | -1.58 |
2.837×1 |

(a) 动电位极化曲线

(b) 平均腐蚀速率
图5 WE43合金和三道次搅拌摩擦加工制备的β-TCP/WE43复合材料在SBF溶液中的腐蚀行为
Fig.5 The corrosion behavior of the WE43 alloy and fabricated β-TCP/WE43 composites through triple passes FSP in the SBF solution
为了验证复合材料的长期腐蚀行为,进一步通过浸泡试验来对β-TCP/WE43复合材料的耐腐蚀性进行测试,通过试验产生的质量损失,来计算复合材料的腐蚀速率,如
通过SEM进一步对三道次FSP制备的β-TCP/WE43复合材料的腐蚀机理进行了分析.WE43合金在模拟体液中浸泡时表面生成疏松 Mg(OH)2沉积层,但该膜层不稳定,易与溶液中的C

图6 三道次搅拌摩擦加工制备的β-TCP/WE43复合材料在SBF溶液中浸泡48 h后的机理分析
Fig.6 Mechanism analysis of β-TCP/WE43 composites through triple passes FSP after 48 h immersion in the SBF solution
(a) 腐蚀形貌;(b) EDS分析;(c)腐蚀机理分析
2.4 摩擦磨损性能
对β-TCP/WE43复合材料进行腐蚀磨损试验,评估其在SBF溶液中的耐磨损性能.如

(a) 摩擦系数随相对滑动距离的变化

(b) 磨损率与负荷的关系
图7 WE43合金和三道次搅拌摩擦加工制备的β-TCP/WE43复合材料在SBF溶液中的腐蚀摩擦行为
Fig.7 Corrosion-wear behavior of the WE43 alloy and β-TCP/WE43 composites through triple passes FSP in the SBF solution

图8 三道次搅拌摩擦加工制备的β-TCP/WE43复合材料在SBF溶液中腐蚀磨损后磨痕和磨屑的形貌以及EDS元素图谱
Fig.8 SEM images and EDS spectrum of the worn surface and wear debris of β-TCP/WE43 composites through triple passes FSP in the SBF solution
(a)腐蚀磨损后的磨痕形貌;(b)去除腐蚀产物后的磨痕形貌;
(c)磨屑形貌
位置 | Mg | O | Ca | P | Na | Cl |
---|---|---|---|---|---|---|
Point 1 | 51.8 | 34.4 | 1.19 | 0 | 0.1 | 1.2 |
3 结 论
本文采用多道次搅拌摩擦加工制备了β-TCP/ WE43复合材料,并对该复合材料的微观组织、力学性能进行了研究,分析了复合材料在模拟体液中的腐蚀行为和摩擦磨损行为,得出以下结论:
1)多道次搅拌摩擦加工有利于β-TCP颗粒在镁基体内的分散和细化晶粒.三道次搅拌摩擦加工制备的β-TCP/WE43复合材料组织细小,搅拌区最大硬度值可达95.7 HV,屈服强度和极限抗拉强度分别达到233.5 MPa和237.9 MPa.
2)在模拟体液中的电化学腐蚀试验表明,三道次搅拌摩擦加工制备的β-TCP/WE43复合材料的腐蚀速率显著降低,腐蚀电流密度减小到2.837×1
A/c
3)摩擦磨损试验结果表明,β-TCP/WE43复合材料的耐蚀磨损性能显著优于WE43合金.在腐蚀磨损情况下,材料本身较好的耐蚀性能协同提高了复合材料在模拟体液环境下的耐磨性,此时磨损机制为轻微的磨粒磨损和腐蚀磨损.
参考文献
ZHAO D W,WITTE F,LU F Q,et al.Current status on clinical applications of magnesium-based orthopaedic implants:a review from clinical translational perspective[J].Biomaterials,2017,112: 287-302. [百度学术]
HORNBERGER H,VIRTANEN S,BOCCACCINI A R.Biomedical coatings on magnesium alloys–A review[J]. Acta Biomaterialia,2012,8(7):2442-2455. [百度学术]
BARTMAŃSKI M,PAWŁOWSKI Ł,STRUGAŁA G,et al.Properties of nanohydroxyapatite coatings doped with nanocopper,obtained by electrophoretic deposition on Ti13Zr13Nb alloy[J].Materials,2019,12(22):3741. [百度学术]
MEHDIZADE M,EIVANI A R,ESMAIELZADEH O,et al.Fabrication of osteogenesis induced WE43 Mg-Hydroxyapatite composites with low biodegradability and increased biocompatibility for orthopedic implant applications[J].Journal of Materials Research and Technology, 2023, 25: 4277-4298. [百度学术]
RADHA R, SREEKANTH D. Insight of magnesium alloys and composites for orthopedic implant applications-a review[J].Journal of Magnesium and Alloys, 2017, 5(3): 286-312. [百度学术]
SEZER N, EVIS Z, KAYHAN S M,et al.Review of magnesium-based biomaterials and their applications[J]. Journal of Magnesium and Alloys, 2018, 6(1): 23-43. [百度学术]
HANAS T,SAMPATH KUMAR T S,PERUMAL G,et al.Electrospun PCL/HA coated friction stir processed AZ31/HA composites for degradable implant applications[J].Journal of Materials Processing Technology,2018,252:398-406. [百度学术]
KIM J,PAN H B.Effects of magnesium alloy corrosion on biological response-Perspectives of metal-cell interaction[J].Progress in Materials Science,2023,133:101039. [百度学术]
GONZALEZ J,HOU R Q,NIDADAVOLU E P S,et al.Magnesium degradation under physiological conditions-best practice[J].Bioactive Materials,2018,3(2):174-185. [百度学术]
SONG G L.Control of biodegradation of biocompatable magnesium alloys[J].Corrosion Science,2007,49(4):1696-1701. [百度学术]
LIN Z J,WU S L,LIU X Y,et al.A surface-engineered multifunctional TiO2 based nano-layer simultaneously elevates the corrosion resistance,osteoconductivity and antimicrobial property of a magnesium alloy[J].Acta Biomaterialia,2019,99:495-513. [百度学术]
SU J L,TENG J,XU Z L,et al.Corrosion-wear behavior of a biocompatible magnesium matrix composite in simulated body fluid[J].Friction,2022,10(1):31-43. [百度学术]
GUSIEVA K,DAVIES C H J,SCULLY J R,et al.Corrosion of magnesium alloys:the role of alloying[J].International Materials Reviews,2015,60(3):169-194. [百度学术]
WU Y L,WU L,YAO W H,et al.Improved corrosion resistance of AZ31 Mg alloy coated with MXenes/MgAl-LDHs composite layer modified with yttrium[J].Electrochimica Acta,2021,374:137913. [百度学术]
SU J L,TENG J,XU Z L,et al.Biodegradable magnesium-matrix composites:a review[J].International Journal of Minerals,Metallurgy and Materials,2020,27(6):724-744. [百度学术]
JAISWAL S,KUMAR R M,GUPTA P,et al.Mechanical,corrosion and biocompatibility behaviour of Mg-3Zn-HA biodegradable composites for orthopaedic fixture accessories[J].Journal of the Mechanical Behavior of Biomedical Materials,2018,78:442-454. [百度学术]
DETSCH R,MAYR H,ZIEGLER G.Formation of osteoclast-like cells on HA and TCP ceramics[J].Acta Biomaterialia,2008,4(1):139-148. [百度学术]
DOROZHKIN S V.Biphasic,triphasic and multiphasic calcium orthophosphates[J].Acta Biomaterialia,2012,8(3):963-977. [百度学术]
LIU D B,ZUO Y B,MENG W Y,et al.Fabrication of biodegradable nano-sized β-TCP/Mg composite by a novel melt shearing technology[J].Materials Science and Engineering:C,2012, 32(5): 1253-1258. [百度学术]
SERRA I R,FRADIQUE R,VALLEJO M C S,et al.Production and characterization of chitosan/gelatin/β-TCP scaffolds for improved bone tissue regeneration[J].Materials Science and Engineering:C,2015,55:592-604. [百度学术]
HUANG Y, LIU D B, ANGUILANO L,et al. Fabrication and characterization of a biodegradable Mg-2Zn-0.5Ca/1 β-TCP composite[J]. Materials Science and Engineering:C,2015,54:120-132. [百度学术]
NARITA K,KOBAYASHI E,SATO T.Sintering behavior and mechanical properties of magnesium/β-tricalcium phosphate composites sintered by spark plasma sintering[J].Materials Transactions,2016,57(9):1620-1627. [百度学术]
ZHANG Y B,YANG H L,LEI S Q,et al. Preparation of biodegradable Mg/β-TCP biofunctional gradient materials by friction stir processing and pulse reverse current electrodeposition[J].Acta Metallurgica Sinica (English Letters),2020,33(1):103-114. [百度学术]
THANGARASU A,MURUGAN N,DINAHARAN I,et al.Synthesis and characterization of titanium carbide particulate reinforced AA6082 aluminium alloy composites via friction stir processing[J].Archives of Civil and Mechanical Engineering,2015,15(2): 324-334. [百度学术]
FARAJI G,DASTANI O,ALI ASGHAR AKBARI MOUSAVI S.Effect of process parameters on microstructure and micro-hardness of AZ91/Al2O3 surface composite produced by FSP[J].Journal of Materials Engineering and Performance,2011,20(9):1583-1590. [百度学术]
ASADI P,FARAJI G,MASOUMI A,et al.Experimental investigation of magnesium-base nanocomposite produced by friction stir processing:effects of particle types and number of friction stir processing passes[J].Metallurgical and Materials Transactions A, 2011, 42(9): 2820-2832. [百度学术]
MD F K,KARTHIK G M,PANIGRAHI S K,et al. Friction stir processing of QE22 magnesium alloy to achieve ultrafine-grained microstructure with enhanced room temperature ductility and texture weakening[J].Materials Characterization,2019,147:365-378. [百度学术]
NGUYEN Q B,GUPTA M.Enhancing compressive response of AZ31B magnesium alloy using alumina nanoparticulates[J].Composites Science and Technology,2008,68(10/11):2185-2192. [百度学术]
ZHANG Z,CHEN D L.Contribution of Orowan strengthening effect in particulate-reinforced metal matrix nanocomposites[J].Materials Science and Engineering:A,2008,483:148-152. [百度学术]
WANG Y,WEI M,GAO J C,et al.Corrosion process of pure magnesium in simulated body fluid[J].Materials Letters,2008,62(14):2181-2184. [百度学术]
BEN HAMU G,ELIEZER D,WAGNER L.The relation between severe plastic deformation microstructure and corrosion behavior of AZ31 magnesium alloy[J].Journal of Alloys and Compounds,2009,468(1/2):222-229. [百度学术]
ARGADE G R, PANIGRAHI S K, MISHRA R S. Effects of grain size on the corrosion resistance of wrought magnesium alloys containing neodymium[J]. Corrosion Science, 2012, 58:145-151. [百度学术]