An investigation on fatigue life assessment of alloy 718 at different load ratio and elevated temperatures

IF 3 2区工程技术 Q2 ENGINEERING, MECHANICAL

International Journal of Pressure Vessels and Piping Pub Date : 2025-04-09 DOI:10.1016/j.ijpvp.2025.105525

Ashutosh Kumar , Qazi Junaid Ashraf , G.A. Harmain

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引用次数: 0

Abstract

Alloy718 is a candidate material for high temperature applications subjected to cyclic loads. Owing to its remarkably high temperature, high strength, fatigue and corrosion resistance properties, it is a widely used structural material especially in demanding environments like gas turbine engine components, nuclear and thermal power plants etc. To investigate the influence of load ratio (0.1, 0.4, and 0.6) and temperatures (650K–800K) on the fatigue life and crack propagation characteristics of the alloy718, tests have been conducted on quarter compact tension (QCT) specimens as per ASTM-E647. FCG life has been observed to increase in an accelerated manner with decrease in temperature or increase in load ratio or both. A rapid increase in FCG life was noticed for tests conducted at load ratio

R = 0.6

irrespective of test temperature. This is further corroborated by fractographic studies, and can be attributed to increase in load ratio (R), which results in decreased stress intensity factor range (ΔK) for increasing R value.

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718合金在不同载荷比和高温下的疲劳寿命评估研究

合金718是经受循环载荷的高温应用的候选材料。由于其显著的高温、高强度、抗疲劳和耐腐蚀性能，它是一种广泛使用的结构材料，特别是在要求苛刻的环境中，如燃气涡轮发动机部件、核电站和火电厂等。为了研究载荷比（0.1、0.4和0.6）和温度（650K-800K）对合金718疲劳寿命和裂纹扩展特性的影响，按照ASTM-E647对四分之一致密拉伸（QCT）试样进行了试验。观察到FCG寿命随着温度的降低或负载比的增加或两者同时增加而加速增加。无论测试温度如何，在负载比R=0.6时进行的测试都注意到FCG寿命的快速增加。断口学研究进一步证实了这一点，并且可以归因于载荷比(R)的增加，从而导致R值增加的应力强度因子范围（ΔK）减小。

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来源期刊

International Journal of Pressure Vessels and Piping 工程技术-工程：机械

CiteScore

5.30

自引率

13.30%

发文量

208

审稿时长

17 months

期刊介绍： Pressure vessel engineering technology is of importance in many branches of industry. This journal publishes the latest research results and related information on all its associated aspects, with particular emphasis on the structural integrity assessment, maintenance and life extension of pressurised process engineering plants. The anticipated coverage of the International Journal of Pressure Vessels and Piping ranges from simple mass-produced pressure vessels to large custom-built vessels and tanks. Pressure vessels technology is a developing field, and contributions on the following topics will therefore be welcome: • Pressure vessel engineering • Structural integrity assessment • Design methods • Codes and standards • Fabrication and welding • Materials properties requirements • Inspection and quality management • Maintenance and life extension • Ageing and environmental effects • Life management Of particular importance are papers covering aspects of significant practical application which could lead to major improvements in economy, reliability and useful life. While most accepted papers represent the results of original applied research, critical reviews of topical interest by world-leading experts will also appear from time to time. International Journal of Pressure Vessels and Piping is indispensable reading for engineering professionals involved in the energy, petrochemicals, process plant, transport, aerospace and related industries; for manufacturers of pressure vessels and ancillary equipment; and for academics pursuing research in these areas.