کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
701451 | 891003 | 2006 | 4 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Thermally activated deformation under Knoop indentations in super-hard directions of high-quality synthetic type-IIa diamond crystals Thermally activated deformation under Knoop indentations in super-hard directions of high-quality synthetic type-IIa diamond crystals](/preview/png/701451.png)
The deformation resistance at room temperature against a Knoop indentation in (001)<110> (the<110> direction on the (001) plane) of high-quality synthetic type-IIa diamond is known to be extremely high. The behavior of deformation in the hard direction activated thermally by heating was investigated, using super-hard Knoop indenters prepared from high-quality diamond crystals by taking the tip orientation to (001)<110>. Indentation tests in (001)<110> with a load of 4.9 N revealed that the formation of normal Knoop impressions arises suddenly at a threshold temperature of 200–240 °C, whereas no impressions are observed up to 200 °C. The hardness values derived from the impressions in (001)<110> formed above the threshold temperatures are as low as 50–60% those in (001)<100> at the same temperatures. The anisotropy in the Knoop hardness at such high temperatures is consistent with the nature of anisotropy predicted by an effective resolved shear stress model for a {111}<110> slip deformation.
Journal: Diamond and Related Materials - Volume 15, Issue 10, October 2006, Pages 1576–1579