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近期发展的铝合金和处理状态提供了强度、韧性、抗应力腐蚀和抗剥落腐蚀等良好的综合性能.这些合金已正用在或准备用在一些飞机上.然而,飞机的可靠性和结构性能的提高,仍然取决于周期载荷裂纹扩展抗力.为了探讨合金成分和最佳抗疲劳裂纹扩展性能的关系,制定了一个测定显微组织和成分对这一性能影响的研究方案.美国空军材料试验室(AFML)报告中提出的全部试验程序、试验前后显微组织的检验、机械性能的测定(抗拉强度、撕裂强度和缺口韧性)以及由2到20兆帕、米~(1/2)的da/dn与ΔK的全部关系曲线,都是适用的.本文的目的是研究中等ΔK值时显微组织与疲劳裂纹的关系.
Recent developments in aluminum alloys and processing conditions provide good overall properties such as strength, toughness, resistance to stress corrosion and exfoliation corrosion, etc. These alloys are already being used or are intended for use on some aircraft, however, the reliability and structural performance of the aircraft Is still dependent on the cyclic loading crack propagation resistance.In order to explore the relationship between the alloy composition and the best anti-fatigue crack growth performance, a research program to determine the effect of microstructure and composition on this property was developed.Final Air Materiel Laboratory (AFML) report, testing of microstructures before and after the test, determination of mechanical properties (tensile strength, tear strength and notch toughness), as well as measurements from 2 to 20 MPa, The relationship between da / dn and ΔK is applicable.The purpose of this paper is to study the relationship between microstructure and fatigue crack under medium ΔK value.