Early Stages of Cu Precipitation in 15-5 PH Maraging Steel Revisited - Part I: Experimental Analysis
Early Stages of Cu Precipitation in 15-5 PH Maraging Steel Revisited - Part I: Experimental Analysis
复制标题
DOI：
10.1002/srin.201600084
复制
发表时间：
2017-01-01
影响因子：
2.2
通讯作者：
Kozeschnik, Ernst
中科院分区：
文献类型：
--
作者：
Primig, Sophie;Stechauner, Georg;Kozeschnik, Ernst
尽管过去已经对二元铁-Cu合金和Cu合金马氏体时效钢等温时效过程中的Cu析出进行了仔细的研究，但到目前为止还没有对连续时效过程中Cu团簇的早期阶段进行详细的研究。15-5 PH马氏体时效钢在差示扫描量热计（DSC）中以15Kmin（-1）的升温速率连续时效时，观察到两个放热反应，一个在300℃左右，另一个在500℃左右。这些DSC信号归因于富铁Cu团簇在较低温度范围内的形核和生长，随后这些团簇富集Cu，并在较高温度下无缝转变为bcc-Cu析出物。本研究的第一部分侧重于以全面的方式控制这些反应的机制的实验表征，其中作者首先提出了基于膨胀法，差示扫描量热法，硬度测试和3D原子探针断层扫描的分析结果。后一种方法能够检测到透射电子显微镜还无法检测到的早期簇。在论文的第二部分中，提出了热动力学模拟，它支持对观察到的反应的解释，并极大地帮助理解潜在的机制。
Even though Cu precipitation during isothermal aging of binary Fe-Cu alloys and of Cu-alloyed maraging steel has been carefully studied in the past, no detailed investigations of the early stages of Cu clustering upon continuous aging have been carried out so far. During continuous aging with a heating rate around 15Kmin(-1) of as-quenched 15-5 PH maraging steel in a differential scanning calorimeter (DSC), two exothermal reactions are observed, one at approximately 300 degrees C and the other one around 500 degrees C. These DSC signals are attributed to the nucleation and growth of Fe-rich Cu clusters in the lower temperature range, followed by Cu-enrichment of these clusters and seamless transformation into bcc-Cu precipitates at higher temperatures. Part I of this investigation focuses on the experimental characterization of the mechanisms governing these reactions in a comprehensive manner, where the authors first present the results of this analysis based on dilatometry, differential scanning calorimetry, hardness testing, and 3D atom probe tomography. The latter method is capable of detecting early clusters, which are not yet accessible by transmission electron microscopy. In the companion paper, part II, thermo-kinetic simulations are presented, which support the interpretation of the observed reactions and substantially aid in understanding the underlying mechanisms.