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单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,复习,三、多孔材料的力学性能,多孔材料结构特点?,有什么用处?,力学性能的特点?,四、非晶合金的力学性能,结构特点?,高硬,、高强度,机理?,有塑性吗?机理?,五、纳米材料的力学性能,纳米金属的超塑性,反霍尔-佩奇关系?,陶瓷纳米复合增韧,复习三、多孔材料的力学性能,1,六、生物材料的力学性能,概述,“天然生物材料”和”生物医用材料”,天然生物材料:,生物医用材料:,假牙、人工髋关节、人工心脏,(b)人工髋关节,(c)心脏瓣膜,(a)齿科植入材料,牙、骨、贝壳、珍珠、蚕丝、蜘蛛丝,六、生物材料的力学性能(b)人工髋关节(c)心脏瓣膜(a)齿,2,蜘蛛丝,放射状骨架丝(纵丝);牵引丝(逃命),反时针织造圆形螺旋丝(横丝),上有粘珠:4%粘性物质+80%水,捕获飞虫,养只蜘蛛保护地球,NASA科学家,巨大的太空蜘蛛,蜘蛛丝的力学性能,韧性是钢筋的6倍,断裂强度800MPa,弹性是尼龙的2倍,拉伸10倍不断裂,,支撑4千倍体重,铅笔粗蜘蛛丝可拦截飞行的波音747客机,优异的能量吸收,如何得知?,蜘蛛侠,天然生物材料的力学性能,10亿经费,蜘蛛侠天然生物材料的力学性能10亿经费,3,蜘蛛丝的力学性能,Yi LIU, Zhengzhong Shao and F. Vollrath,Relationships between supercontraction and mechanical properties of spider silk,nature materials,VOL 4 2005,断裂强度800-1400MPa,优异的能量吸收,蜘蛛丝的力学性能 Yi LIU, Zhengz,4,浙大材料力学15-材料力学性能课件,5,为什么有如此性能?,什么样的结构?,为什么这种结构具有特殊的力学性能?,如何获得这种结构?,半结晶超分子结构,2003,Nature,捕获丝的超分子结构,微观结构!,养蜘蛛?人工制备?,其他文献?,半结晶超分子结构2003 Nature捕获丝的超分子,6,结构,“叠层砖墙式复合”结构,超薄CaCO3(95%)+纳米厚度的有机物,性能,硬度为CaCO3的2倍;韧性为其1000倍,贝壳的力学性能,机理?,类型,晶体,蛋白质基体,(wt%),强度 / MPa,硬度MPa,拉伸,压缩,弯曲,棱柱,方解石,1%4%,60,250,140,162,珍珠层,文石,1%4%,130,380,220,168,交叉叠层,文石,0.01%4%,40,250,100,250,簇叶,方解石,0.1%0.3%,30,150,100,110,均匀分布,文石,/,30,250,80,/,200nm,+5nm,机理?类型晶体蛋白质基体强度 / MPa硬度MPa拉,7,0.5mm厚,500,m=510,5,nm,200nm宽,厚度方向有2500块砖,位移5nm,总位移12500nm=12.5,m,变形量:12.5/500=2.5%,1cm长,10mm=110,4,m,砖长2m,砖数量:10000/2=5000块,位移5nm,总位移=25m,变形量:25/10000=2.5%,0.5mm厚,8,机理,片层间相互滑移 断裂前能经受较大的塑性变形,裂纹沿层片间的有机层扩展 阻止裂纹的穿透扩展,开裂,片层之间摩擦力(拔出) 消耗裂纹扩展能量,1.0,1.0,珍珠层裂纹扩展过程的原位观察,机理1.01.0珍珠层裂纹扩展过程的原位观察,9,Freezing as a Path to Build Complex Composites,Sylvain Deville, Eduardo Saiz, Ravi K. Nalla, Antoni P. Tomsia,SCIENCE,VOL 311 27 JANUARY 2006,如何制备?,Freezing as a Path to Build Co,10,Fig. 1. Processing principles and materials,While the ceramic slurry is freezing, the growing ice crystals expel the ceramic particles, creating a lamellar microstructure oriented in a direction parallel to the movement of the freezing front (A).,Dense composites are obtained by infiltrating the porous lamellar ceramic with a second phase (e.g., a polymer or a liquid metal).,Natural nacre has a brick-mortar-bridges microstructure:,B, C, D. E, F: the aluminaAl-Si composite,Fig. 1. Processing principles,11,水的凝固-相变,水知道答案,田园交响曲,离别曲,水的凝固-相变水知道答案田园交响曲,12,Fig. 3. Mechanical response of natural and synthetic IT composites.,The three-points bending load-displacement,data for IT HAP-epoxy composites,(A) was qualitatively very similar to that of nacre (C),SEM of the IT composites (B) and nacre (C) reveal similar features on the fracture surface.,Extensive crack deflection at the organic-inorganic interface results in tortuous crack paths and contributes to the toughening in both cases (D).,The role of the interfacial chemistry in the bonding between layers and the final mechanical properties of the material is illustrated in the data (E) for aluminaAl-Si composites (45/55 vol %); the addition of 0.5 wt % titanium to the aluminum alloy significantly increases the strength and toughness of the materials.,Fig. 3. Mechanical response of,13,如何制备出更好的?,可开展更多研究,砖的大小、厚度如何控制?,粘结剂如何填充进去?,力学性能的定量表达式?,砖的形状,如何制备出更好的?可开展更多研究,14,海胆牙齿不钝之谜, 皮质骨的力学性能,性能指标,加载方向与骨干,平行,垂直,拉伸强度/MPa,124174,4951,压缩强度/MPa,170193,133,弯曲强度/MPa,160,弹性模量/GPa,17.018.9,11.5,剪切模量/GPa,3.3,K,IC,/MPam,1/2,212,表 牙齿的力学性能,牙本质,牙釉质,抗压强度/MPa,300,330,硬度Hv,70,300,生物材料的力学性能,力学性能检测 表 皮质骨的力学性能加载方向与骨干,18,生物医用金属材料,表 几种生物医用金属材料的力学性能,密度,g/cm,3,弹性模量,GPa,硬度,Hv,压缩强度,MPa,抗拉强度,MPa,延伸率,%,不锈钢,F55退火态,7.9,200,183,170,465,40,F55冷加工,7.9,200,320,690,850,12,钴基,合金,铸CoCrMo,退火态,7.8,200,300,455,665,10,锻,CoCrMo退火态,9.15,230,240,390,880,30,锻CoCrMo,冷加工,9.15,230,450,1000,1500,9,钛基,合金,Ti退火态,4.5,127,260,443,563,15,Ti6Al4V,退火态,4.4,127,330,830,900,8,不锈钢、钴基和钛基合金,高的机械强度和抗疲劳性能,表 几种生物医用金属材料的力学性能密度弹性模量硬度,19,材料:Al2O3、ZrO2,,羟基磷灰石,等,优点:生物相容性,较好,缺点:脆,,因此常用在表面,骨骼系统的修复和替换,表 几种生物医用陶瓷材料的力学性能,密度,g/cm,3,弹性模量,GPa,硬度,Hv,压缩强度,MPa,抗拉强度,MPa,Al,2,O,3,高纯态,3.93,380,2300,550,4500,C,低温各向同性态,1.62.2,1828,150250,280560,/,玻璃态,1.41.6,2431,150250,70210,/,超低温各向同性态,1.52.2,1421,150250,350700,/,ZrO,2,热等静压烧结态,6.1,200,1300,1200,/,生物医用陶瓷材料,表 几种生物医用陶瓷材料的力学性能密度弹性模量硬度压缩强度,20,前述材料的复合,生物、力学等性能的优化,人和动物体中绝大多数是复合材料,表 几种生物医用复合材料的力学性能,密度,g/cm,3,弹性模量,GPa,压缩强度,MPa,抗弯强度MPa,最小延伸率,%,聚甲基丙烯酸甲酯,/,5.52,/,38,0.7,C60SiC,2.6,100,1000,220,1,C60SiC (5%孔隙率),2.4,8090,250370,220360,/,碳纤维增强碳,1.7,140,800,800,4,环氧树脂12.5碳,/,14,/,200,/,连续碳纤维增强聚砜,/,110,/,1600,1.3,超高分子聚乙烯,0.98,1.94,14.2,22,150,生物医用复合材料(高分子材料),表 几种生物医用复合材料的力学性能密度弹性模量压缩,21,其他力学性能,耐久性(寿命。疲劳、磨损),人造导管:人体血管内工作3天以上,金属骨钉:6个月以上,心脏瓣膜:每分钟弹跳约60次,寿命不低于10年,髋关节:10年以上,新材料及其力学性能?,人造肌肉、血管等?强度?延伸率?,超高分子量聚乙烯,髋臼杯,形状记忆合金及其力学性能特点?,钴基合金的耐磨性?,医用镁合金的力学性能-能达到要求吗?,其他力学性能,22,
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