Enhancement of hardness, modulus and fracture toughness of the tetragonal (Fe,Cr)2B and orthorhombic (Cr,Fe)2B phases with addition of Cr
Enhancement of hardness, modulus and fracture toughness of the tetragonal (Fe,Cr)2B and orthorhombic (Cr,Fe)2B phases with addition of Cr
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DOI：
10.1016/j.matdes.2018.06.040
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发表时间：
2018-10-15
影响因子：
8.4
通讯作者：
Theisen, Werner
中科院分区：
文献类型：
--
作者：
Lentz, Jonathan;Roettger, Arne;Theisen, Werner
采用纳米压痕法研究了Cr含量对M2 B硼化物硬度H、弹性模量E和断裂韧性K-IC的影响。此外，还测定了Fe-3（C，B）相的性质。通过扫描电子显微镜、能谱仪和X射线衍射仪对M2 B相样品进行了测试和微观结构表征。在Cr含量高于14.7原子%时，M2 B相从四方晶系转变为正交晶系结构。在4-5原子% Cr时，四氢呋喃M2 B型具有H（21 +/- 1 GPa）、E（373 +/- 6）GPa和K-IC（3.5 +/- 0.7 MPa均方根）的最佳值。正交M2 B相的硬度、模量和韧性随着Cr含量增加而增加，并且在最大研究的Cr含量为55原子%时达到H = 27 +/- 0.7 GPa、E = 473 +/- 9和K-IC = 3.26 +/- 0.8 MPa根m的值。M2 B相的硬度随着压痕深度的增加而降低约2.3- 3.2GPa，这被称为压痕尺寸效应。M2 B相的硬度和断裂韧性优于常规使用的M7 C3碳化物，并且与MC-碳化物相似。研究结果可用于新的合金化方法，以优化工具钢的性能和降低成本。(C)2018爱思唯尔有限公司版权所有
This study analyzes the influence of Cr content on hardness H, elastic modulus E and fracture toughness K-IC of the M2B boride by means of nanoindentation experiments. Additionally, properties of the Fe-3(C,B) phase are determined. Samples of the M2B phase are tasted and microstructurally characterized by means of scanning electron microscopy, energy dispersive spectroscopy and X-ray diffraction. At a Cr content higher than 14.7 atom% the M2B phase transforms from tetragonal into orthorhombic structure. The tetragonal M2B type possesses an optimum of H (21 +/- 1 GPa), E (373 +/- 6) GPa and K-IC (3.5 +/- 0.7 MPa root m) at 4-5 atom% Cr. The hardness, modulus and toughness of the orthorhombic M2B phase increase with Cr content and reach values of H = 27 +/- 0.7 GPa, E = 473 +/- 9 of and K-IC = 3.26 +/- 0.8 MPa root m at maximal investigated Cr content of 55 atom%. The hardness of the M2B phases decreases around 2.3-3.2 GPa as a function of indentation depth, which is known as the indentation size effect. Hardness and fracture toughness of M2B phase outperform conventionally used M7C3 carbides and are similar to MC-carbides. Findings can be used in novel alloying approaches in order to optimize the performance and reduce cost of tool steels. (C) 2018 Elsevier Ltd. All rights reserved.