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1.
压痕法测定热压MoSi2基复合材料K1C值的研究 总被引:8,自引:1,他引:8
用不同的压痕方程计算了纳米ZrO2粒子韧化MoSi2基复合材料的室温断裂韧性K1c值,同时研究了压痕载荷对K1c值的影响。结果表明,试验材料在试验条件下的断裂韧性不遵从半月状裂纹系统方程,而遵从巴氏裂纹系统方程,其室温压痕断裂韧性保持与压痕载荷的独立性。 相似文献
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周期阵列压痕方法是研究微观摩擦学的工具之一。由于周期阵列刚性压头压在半平面弹性体的表面时,会产生周期的Ⅰ型奇异压应力场,该奇异应力场的应力集中达到一定程度时,即达到临界条件时,该奇异应力场所在的边界将开裂。压痕边界的开裂问题是一个新型的断裂力学问题,通过边界移动的能量释放率的分析给出了压痕边界开裂能量释放率数学表征,并给出边界开裂的临界载荷和临界开裂角。 相似文献
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当二维平端刚性压头作用在镀层基体的表面时,在镀层材料的表面形成一个平面压痕,同时在压痕的边界处将诱生奇异应力场和K-控制区。与裂纹问题类似,该应力场的平面压痕应力强度因子是描述奇异应力场应力集中程度的唯一参量。本文将利用守恒积分,讨论镀层基体平面压痕守恒积分的主要特征,同时给出镀层基体平面压痕应力强度因子的远场积分计算方法。 相似文献
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藉助于声发射技术,研究了在 Vickers 钻石压头作用下人工水晶的压痕断裂行为。压头对角线与晶体试样的相对取向是,使得水晶Ⅰ和水晶Ⅱ的压痕诱发径向/中位断裂,分别沿着(10(?)0)/(1(?)10)和(11(?)0/(1(?)00)晶面对发展。压痕断裂过程中的声发射特征表明,除了随着压痕特征参数的发展所引起的准静态—声发射外,有三个相互独立的,与径向/中位裂纹的成核、径向/中位裂纹突入试样表面、以及裂纹分岔或侧向裂纹萌生等过程相关的声发射效应。以 Vickers 压痕技术测得 K_(c2)的结果与以一般力学法及 Knoop 压痕技术的测试结果作了比较。断裂韧性与晶体学取向的关系亦作了分析。实验表明,水晶Ⅰ和水晶Ⅱ具有相同的 K_(1c)值。其原因是,两种试样的径向/中位裂纹实际上沿着同样的{1100}/{1120}晶面对扩展。至于从缺口梁法或 Knoop 压痕技术得到的 K_(1c)值,由于水晶Ⅰ和水晶Ⅱ的主裂纹分别沿着(1(?)10)和(1(?)00)晶面扩展;它们的 K_(1c)值与断裂能随着晶体学取向而变有关,因而也就各不相同。 相似文献
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《Microelectronics Reliability》2014,54(9-10):1959-1962
Managing the emerging internal mechanical stress in chips, particularly if they are 3D stacked, is a key task to maintain performance and reliability of microelectronic products. Hence, a strong need of a physics-based simulation methodology emerges. This physics-based simulation, however, requires material parameters with high accuracy. A full-chip analysis can then be performed, balancing the need for local resolution and computing time. The key for an efficient simulation of a 3D stacked IC is a comprehensive database with material properties for multiple scales of the affected materials. Therefore, effective “composite-type” material data for several regions of interest are needed. Advanced techniques to measure FEA- and design-relevant properties such as adhesion properties and effective CTE values are presented. 相似文献
9.
《Journal of the European Ceramic Society》2017,37(15):4437-4441
Poor correlation between indentation fracture resistance, KIFR, and fracture toughness, KIC, has long been considered a weak point of the indentation fracture (IF) method of materials analysis. The present work therefore assessed the reliability of the experimental data that has historically been used for comparisons of KIFR and KIC. A painstaking survey of primary literature reports concerning the IF method revealed that the comparisons of KIC with KIFR in most studies were imperfect because both KIC and KIFR were measured using unreliable techniques and because improper test materials such as silicate glass were employed. These findings indicate that the standard objections against the use of the IF model are not well supported, and also that the majority of the empirically-derived calibration constants used in various IF equations are suspect. Accordingly, it is evident that new experimental measurements using the latest and most reliable techniques will be required to allow well-informed discussions of the validity of this test method in future. 相似文献
10.
《Journal of the European Ceramic Society》2014,34(14):3407-3412
Indentation fatigue of WC grains on basal and prismatic planes in WC–Co cemented carbide has been investigated using instrumented indentation at nano level and applied loads from 5 mN to 50 mN. The influence of indentation load and crystallographic orientation of WC grains has been studied. Scanning electron microscopy (SEM), electron backscattered diffraction (EBSD) and atomic force microscopy (AFM) have been used for the characterization of microstructure, orientation of WC grains, topography of indents and slip lines in WC grains. Significant influence of the crystallographic orientation of WC grains on the indentation fatigue has been found. The indentation depth increased with the increasing load more intensively during the fatigue test of the prismatic planes than the basal planes. This behavior is probably connected with the different slip and dislocation mechanisms during the indentation of basal and prismatic planes. 相似文献