材料的滞弹性与内耗..ppt

过去曾经认为，由于面心立方晶体中的间隙原子引起溶剂点阵的畸变是立方对称的，因而不存在应力感生有序的倾向。但1953年洛辛和芬克尔斯坦在含碳奥氏体不锈钢Cr25Ni20中观察到： 2）洛辛峰——fcc晶体中间隙原子引起的内耗 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 葛庭燧等人研究了碳在Cr18Ni8不锈钢、高锰钢、镍铝合金以及纯镍中所引起的内耗，结果表明，间隙原子在面心主方晶体中引起内耗是一个普遍现象。他们用湿氢脱碳和渗碳的方法来改变碳的含量得到碳含量与Q-1峰高成正比的关系。 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. B：置换原子 C：间隙原子 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 3）甄纳峰——置换原子引起的内耗 首先在Cu70Zn30合金中发现在400 ℃，620Hz处有很明显的内耗峰； 后发现在Ag-Zn合金中这种内耗峰更明显； 在bcc、fcc、hcp中发现20种合金都有类似的内耗峰。 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 2 与位错有关的内耗 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. K-G-L理论 强钉 弱钉 弓出 雪崩 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 3 与晶界有关的内耗 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 第八章 材料的滞弹性与内耗 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. §1 材料的滞弹性 一 滞弹性的定义 1 理想弹性：在振动条件下，应力和应变之间的关系完全遵从胡克定律，应力与应变随时保持同相位。 理想粘弹性：粘性服从牛顿定律，应力与应变速率成正比。聚合物的粘弹性是严重发展的滞弹性。 滞弹性：是指在弹性范围内出现的非弹性现象。应变不仅与应力有关，而且与时间有关。 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 二 滞弹性的力学模型 1 弹性及粘性元件模型： 2 滞弹性的力学模型： 标准线性固体力学模型 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspos