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无机非金属材料的强化-钢化、增强、增韧、抗裂,严建华,Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.,以下日常生活的经验可让我们更好理解无机材料的力学性能,碗打破 钢筋混凝土 玻璃摔碎 玻璃钢 割玻璃 预应力混凝土 混凝土断裂 弯钢管 砖的破碎 折断毛竹筷子 瓷砖的破碎 折断塑料 钢化玻璃 盐粒的碎裂,Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.,由以上我们可以总结出,无机材料的断裂行为和金属材料不同,其断裂行为的本质特征是脆性断裂。 脆性断裂以在很小的应变情况下就断裂为特征,相比而言,金属断裂的应变为10%左右,聚合物断裂时的应变为3%,而陶瓷的断裂应变为0.05% ,也就是说,几乎看不到到应变断裂就发生了。,Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.,格里菲斯强度理论,Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.,问题在哪里!,Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.,让我们从最典型的硅酸盐-二氧化硅的结构说起。,Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.,二氧化硅的基本结构单元,Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.,二氧化硅的空间结构,Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.,有规则网络的破坏石英晶体的熔化,Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.,钠钙硅玻璃中钙离子对钠离子溶出的阻碍作用,Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.,玻璃的强度形成过程,Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.,玻璃的抗张强度和抗压强度的计算方法,Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.,玻璃的抗张强度和抗压强度计算系数,Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.,影响玻璃强度的其他性质,1、微不均匀性(200埃左右):分相及未熔化均匀.此处简述玻璃的分相. 2、微观缺陷:结石.气泡等夹杂物 3 、表面微裂纹 4 、活性介质(水和酒精的区别) 5 、高于200度,呈塑性断裂 6 、应力(啤酒瓶的破坏,钢化玻璃),Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.,陶瓷的显微结构-1,Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.,陶瓷的显微结构-2,Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.,陶瓷的上釉在一定程度上也有强化陶瓷的作用,1、裂纹的填充 2、陶瓷内部吸水性的降低(降低裂纹端部腐蚀倾向),Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.,陶瓷强度的形成过程,陶瓷是由粉末经过成型烧成而得到的块状物质,其中还存在致密化过程中未能充分排出的气体所形成的气泡.是基体以化学键(主要是共价键和离子键)结合的含有气孔的复相结构.颗粒之间的化学键是陶瓷烧成过程中通过扩散等途径而形成的.,Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.,陶瓷强度的影响因素,1 、晶相强度 2 、玻璃相强度 3 、气孔的问题 4 、基相和晶相的结合强度 5 、晶相的形状(针状或粒状) 6 、晶项和玻璃相的比例,Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.,结论,典型硅酸盐材料中,低温条件下共价键的方向性和离子键的局域性决定了无机材料的脆性断裂行为!,Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.,增加玻璃强度的措施,1、提高玻璃中强化学键氧化物的比例(石英玻璃) 2 、减小玻璃的不均匀应力(退火) 2、 减小微裂纹对玻璃强度的影响(抛光热塑包封和钢化) 3、使玻璃断面变得粗糙(微晶玻璃) 4、抗拉情况下,使玻璃的拉伸方向和裂纹方向相同(玻璃纤维),Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.,高硅氧玻璃,石英玻璃由于二氧化硅键强大,因而是强度最好的玻璃,但也是由于其原料二氧化硅键强大,因而需要很高的熔化温度才能实现熔化过程.并且石英玻璃在熔化过程中挥发较大,因而,由二氧化硅熔制石英玻璃工艺难度大,高硅氧玻璃的制造是一种在较低工艺条件下制造石英玻璃的工艺.,Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.,高硅氧玻璃制造工艺,玻璃熔制 玻璃成型 玻璃分相,酸浸泡溶出,多孔玻璃,烧结,多孔玻璃,600左右,(1200 ),Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.,硼硅酸盐玻璃的分相,Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.,分相热力学条件: 液相的自由焓组 成曲线存在正弦 波的形式,Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.,亚稳分相的实例-玻璃的分相,Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.,不同的分相形貌,Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.,酸熔后的多孔玻璃为何能在较低温度烧结,1玻璃相储藏能量 2表面张力的作用使玻璃在加热过程中表面有尽量减小的趋势,Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.,玻璃的剩余能量,Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.,微晶玻璃提高强度的三个基本点,1在组成相同时,晶态物质的强度一般大于玻璃态(因为玻璃态空旷和微不均匀性大) 2微晶玻璃的断面较玻璃更为粗糙. 3相比同组成的陶瓷而言,微晶玻璃没有气孔,也就是没有断裂的薄弱环节.,Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.,微晶玻璃的制造,玻璃熔制 成型 核化 晶化 成核剂加入的必要性.
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