It is developed and derived that the ductile/brittle transition is located at ${\nu }^{*}$=2/3 where ${\nu }^{*}$is the renormalized form of the standard Poisson's ratio. This is for homogeneous and isotropic materials in the state of uniaxial tension. This then converts to the ductile/brittle transition as being established at $\mu /k$ =1/2 where $\mu$ and k are the shear and bulk moduli. The consequences of these results for the elements of the Periodic Table are surveyed. It is found that the ductile/brittle transition occurs at or very near to the element iron. Nevertheless these results apply more generally than just to the elements and they have far reaching implications. They reveal a fundamental and specific relationship between the elastic properties of materials and the failure properties of materials. These developments validate and generalize the insightful but empirical observations of Pugh [7] given 66 years ago.

得出并得出延性/脆性转变位于 ${\nu }^{*}$= 2/3其中 ${\nu }^{*}$是标准泊松比的规格化形式。这是针对单轴拉伸状态下的均质和各向同性材料。然后将其转换为在以下位置确定的延性/脆性转变$\mu /ķ$ = 1/2其中 $\mu$和k是剪切模量和体积模量。对这些结果对元素周期表中元素的影响进行了调查。发现在元素铁处或非常接近元素铁处发生延性/脆性转变。然而，这些结果不仅仅适用于要素，而且具有更广泛的意义。它们揭示了材料的弹性特性和材料的破坏特性之间的基本和特定的关系。这些发展证实并概括了66年前Pugh [7]提出的有见地但基于经验的观察。