Can high strength and moderate ductility be combined in wear resistant coatings? A fundamental plasticity study of X2BC nanolaminates (X=Hf, Mo)

耐磨涂层能否将高强度和中等延展性结合起来？

• 批准号: 316303762
• 负责人: Professor Dr. Gerhard Dehm
• 金额: --
• 依托单位: Lehrstuhl für Werkstoffchemie (MCh)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2016
• 资助国家: 德国
• 起止时间: 2015-12-31 至 2019-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/316303762?language=en
• 关键词: strength; moderate; ductility; combined; wear

In situ synchrotron X-ray diffraction experiments and small scale mechanical studies supported by electron microscopy will be conducted to delineate the relationship between coating stress and strain with the plastic behavior of Mo2BC. We seek to identify the fundamental mechanisms that govern the plastic behavior of X2BC nanolaminates (X=Hf, Mo) and compare these results to previously published and here obtained quantum mechanical predictions. Since our initial micro mechanical data support the notion of moderate ductility predicted by the quantum mechanical calculations this project aims at answering the following questions linking microstructural characteristics with the mechanical properties: 1. Does the microstructure of X2BC nanolaminate (X=Hf, Mo) coatings influence their mechanical behavior? The microstructure in coatings is controlled by the deposition parameters such as deposition temperature, deposition rate, and degree of ionization of the film forming species. We will deposit fully amorphous, fully crystalline coatings as well as films with various amorphous to crystalline phase fractions. TEM will be employed to determine the domain sizes of the crystalline and amorphous regions and, together with XRD, also the domain size of the crystalline regions for the fully crystalline films. In situ mechanical straining will be performed for different microstructures of X2BC nanolaminate (X=Hf, Mo) coatings. The influence of internal stresses and phase fraction and domain size on the mechanical behavior will be studied. Wafer curvature measurements are performed to assess the stress state of the as-deposited coatings. XRD is used to determine the stress (strain) in the crystalline regions of the coating and the mean sizes of the crystalline domains in the coatings. 2. What deformation mechanisms are active in X2BC nanolaminates (X=Hf, Mo)? Typically, layered solids such as MAX phases are known as plastically anisotropic materials. Upon loading, such solids deform by glide of basal plane dislocations. The formation of Kink Bands (KBs) was also reported as a consequence of the plastic anisotropy of the MAX phases. Based on post mortem TEM experiments, we aim for the characterization of the dislocations structure and its interaction with other microstructural features in order to identify and understand the deformation mechanism active in amorphous and nanocomposite (nanocrystals in an amorphous matrix) and fully crystalline X2BC coatings. 3. Does B/G and the Cauchy pressure serve as predictors for the plastic behavior of X2BC nanolaminates (X=Hf, Mo) While Mo2BC was predicted to behave moderately ductile, Hf2BC is expected - based on both, Cauchy pressure and B/G to be brittle. Hence, a comparative investigation of these two nanolaminate systems will shed light on the question as to the predictive capability of B/G and the Cauchy pressure and potential limits thereof for nanolaminates.

将进行原位同步加速器X射线衍射实验和电子显微镜支持的小规模机械研究，以描绘MO2BC的塑性行为与涂层应力与应变之间的关系。我们试图确定控制X2BC纳米胺（X = HF，MO）的塑性行为的基本机制，并将这些结果与先前发表的结果进行比较，并在此获得量子机械预测。由于我们的初始微型机械数据支持量子机械计算预测的中度延展性的概念，因此该项目旨在回答以下问题，将微观结构特征与机械性能联系起来：1。X2BC纳米氨基氨酸酯（X = HF，MO）涂层的微观结构是否影响其机械行为？涂料中的微观结构由沉积参数（例如沉积温度，沉积速率和膜形成物种的电离程度）控制。我们将沉积完全无定形的完全结晶涂层以及具有各种无定形至结晶相位的膜。 TEM将被用来确定晶体和无定形区域的域大小，并与XRD一起，也是全晶膜的结晶区域的域大小。将对X2BC纳米氨基酸盐（X = HF，MO）涂层的不同微结构进行原位机械拉力。将研究内部应力，相位分和域大小对机械行为的影响。进行晶圆曲率测量，以评估沉积涂层的应力状态。 XRD用于确定涂层晶体区域中的应力（应变）和涂料中晶体结构域的平均大小。 2。X2BC纳米胺（X = HF，MO）中有哪些变形机制？通常，分层固体（例如最大相）被称为塑料各向异性材料。加载后，这种固体通过基础平面位错的滑动而变形。还报道了最大相的塑性各向异性，还报道了扭结条带（KBS）的形成。根据验尸后的实验，我们旨在表征错位结构及其与其他微观结构特征的相互作用，以识别和理解无定形和纳米复合材料中活性的变形机制（无定形基质中的纳米晶体）和完全结晶的X2BC涂料。 3。do b/g和cauchy压力作为X2BC纳米胺（X = HF，MO）的塑性行为的预测因子，而MO2BC预计将表现中适中的延性，HF2BC的预期 - 基于Cauchy，Cauchy压力和B/G脆弱。因此，对这两种纳米氨酸盐系统的比较研究将阐明有关B/G的预测能力以及纳米酰胺的cauchy压力以及其潜在限制的问题。

项目成果

Thermal stability of nanocomposite Mo2BC hard coatings deposited by magnetron sputtering

• DOI: 10.1016/j.surfcoat.2018.06.006
• 发表时间: 2018-09
• 期刊: Surface and Coatings Technology
• 影响因子: 5.4
• 作者: S. Gleich;B. Breitbach;N. Peter;R. Soler;H. Bolvardi;J. Schneider;G. Dehm;C. Scheu

Correlative Experimental and Theoretical Investigation of the Angle-Resolved Composition Evolution of Thin Films Sputtered from a Compound Mo2BC Target

复合 Mo2BC 靶材溅射薄膜角度分辨成分演化的相关实验和理论研究

• DOI: 10.3390/coatings9030206
• 发表时间: 2019
• 期刊: Coatings
• 影响因子: 3.4
• 作者: J.-O. Achenbach;S. Mráz;D. Primetzhofer;J.M. Schneider
• 通讯作者: J.M. Schneider