Blavette D, Cadel E, Fraczkiewicz A, Menand A
Sonde Atomique et Microstructures, Groupe de Metallurgie Physique, UMR CNRS 6634, Faculte des Sciences de Rouen, Universite de Rouen, 76821 Mont-Saint-Aignan Cedex, France.
Science. 1999 Dec 17;286(5448):2317-9. doi: 10.1126/science.286.5448.2317.
Clouds of impurity atoms near line defects are believed to affect the plastic deformation of alloys. Three-dimensional atom probe techniques were used to image these so-called Cottrell atmospheres directly. Ordered iron-aluminum alloys (40 atomic percent aluminum) doped with boron (400 atomic parts per million) were investigated on an atomic scale along the <001> direction. A boron enrichment was observed in the vicinity of an <001> edge dislocation. The enriched region appeared as a three-dimensional pipe 5 nanometers in diameter, tangent to the dislocation line. The dislocation was found to be boron-enriched by a factor of 50 (2 atomic percent) relative to the bulk. The local boron enrichment is accompanied by a strong aluminum depletion of 20 atomic percent.
人们认为，位错线附近的杂质原子云会影响合金的塑性变形。三维原子探针技术被用于直接成像这些所谓的科垂尔气团。对掺杂硼（百万分之400原子分数）的有序铁铝合金（铝原子分数为40%）沿<001>方向进行了原子尺度的研究。在<001>刃型位错附近观察到硼的富集。富集区域呈现为直径5纳米的三维管道，与位错线相切。发现位错处的硼相对于基体富集了50倍（2原子分数）。局部硼的富集伴随着20原子分数的强烈铝贫化。
