延展性是衡量材料在断裂前发生显著塑性变形的能力,通常用伸长率或面积缩小率来量化。韧性材料,如钢,在其应力-应变曲线上显示出较长的塑性区域。脆性则与此相反;陶瓷或铸铁等脆性材料在断裂时几乎不会发生塑性变形。.

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延展性是衡量材料在断裂前发生显著塑性变形的能力,通常用伸长率或面积缩小率来量化。韧性材料,如钢,在其应力-应变曲线上显示出较长的塑性区域。脆性则与此相反;陶瓷或铸铁等脆性材料在断裂时几乎不会发生塑性变形。.
The distinction between ductile and brittle behavior is clearly visible on the stress-strain curve. A ductile material exhibits a significant strain after the yield point and before the fracture point. This large area under the curve after yielding indicates that the material can absorb a great deal of energy before it breaks. This property is crucial for safety in many engineering applications, as a ductile failure provides a visible warning (e.g., bending or stretching) before a complete collapse. Key measures of ductility are percent elongation, [latex](\frac{L_f – L_0}{L_0}) \times 100[/latex], and percent reduction in area, [latex](\frac{A_0 – A_f}{A_0}) \times 100[/latex], where the ‘f’ subscript denotes the final dimension at fracture.
相反,脆性材料在达到弹性极限后,应变非常小。断裂应力通常接近极限拉伸强度,失效会突然发生,且没有任何预兆。陶瓷、玻璃和一些聚合物就是典型的例子。材料的行为也可能取决于外部条件。例如,许多在室温下具有延展性的钢在低温下会经历延展性到脆性的转变,这种现象曾导致灾难性的破坏,例如二战期间的自由轮。
延展性和脆性
(如果日期未知或不相关,例如“流体力学”,则提供其显著出现的近似估计)
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