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单晶及粗晶各向异性高强度合金是燃汽涡轮常用的构件材料。在应变控制疲劳试验中,采用通常的应变测量方法往往有一定的局限性。本文拟在分析这些局限性因素的基础上介绍一种用于测量试样肩部位移的轴向引伸计,并对这种应变测量方法作出评价。一高温疲劳试验中有关问题的分析目前在全反复应变控制疲劳试验中已发展了多种方法用以可靠地将试样夹持在夹头内。例如英国皇家空军试验室采用带螺纹和锥形头部的试样(图1)。试样的锥形头部压入夹头并用螺母锁紧(图2)。试样锥端的压力应大于试验的最大拉伸负荷,以防止螺纹松动。为了便于将经过高温试验后的试样取下,螺纹部分有较大锥度并被截短。试样变形可用轴向或径向引伸计监控。径向应变测量可用漏斗形或标距极短的试
Single crystal and coarse grain anisotropic high-strength alloys are commonly used in gas turbine components. In the strain control fatigue test, the usual strain measurement methods often have some limitations. This paper intends to analyze the limitations of these factors based on the introduction of a sample for measuring the shoulder displacement of the axial extensometer, and evaluation of this strain measurement method. Analysis of Related Problems in a High-Temperature Fatigue Test There are several methods currently developed in Fatigue Testing for Fully-repeated Strain Control to reliably hold a specimen in a chuck. For example, RAF laboratories use a sample with a threaded and tapered head (Figure 1). The tapered head of the specimen is pressed into the chuck and locked with a nut (Figure 2). The pressure at the cone end of the specimen shall be greater than the maximum tensile load of the test to prevent loosening of the threads. In order to facilitate the removal of the sample after the high temperature test, the thread portion has a larger taper and is truncated. Sample deformation can be measured with an axial or radial extensometer. Radial strain measurement available funnel-shaped or very short gauge test