Ultra Low-Cycle Fatigue Behavior Comparison between Additively Manufactured and Rolled 17-4 PH (AISI 630) Stainless Steels
Ultra Low-Cycle Fatigue Behavior Comparison between Additively Manufactured and Rolled 17-4 PH (AISI 630) Stainless Steels
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DOI：
10.3390/met11111726
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发表时间：
2021-10
期刊：
影响因子：
2.9
通讯作者：
David Gonzalez-Nino;Timothy Strasser;G. Prinz
中科院分区：
文献类型：
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作者：
David Gonzalez-Nino;Timothy Strasser;G. Prinz
本研究研究了增材制造 (AM) 17-4 PH (AISI 630) 不锈钢的机械行为，并将其行为与传统生产的锻造不锈钢进行比较。本研究的目的是了解在 ULCF 条件下影响 AM 17-4 PH 钢疲劳寿命的关键参数，并开发简单的预测模型来估计 AM 17-4 钢部件的疲劳寿命。在这项研究中，增材制造和传统生产（锻造）材料样品均在完全反向（R = -1）应变控制（2-4% 应变）载荷下进行疲劳测试，并使用显微硬度、X 射线衍射和断口分析方法进行表征。结果表明，与锻造 17-4 PH 样品相比，增材制造样品的疲劳寿命缩短，这是由于制造孔隙度和未熔化的颗粒缺陷区域提供了内部断裂引发的机制。这项工作中对增材制造和锻造样品进行的热处理工艺对 ULCF 行为没有明显影响。与现有疲劳预测模型（Coffin-Manson 通用斜率方程）的结果比较表明，在施加应变幅度大于 3% 时，疲劳寿命的预测一致过高，这可能是由于固有的增材制造制造缺陷造成的。本文提出了另一种经验 ULCF 容量方程，以帮助将来对 AM 17-4 PH 不锈钢部件进行疲劳估计。
This study investigates the mechanical behavior of additively manufactured (AM) 17-4 PH (AISI 630) stainless steels and compares their behavior to traditionally produced wrought counterparts. The goal of this study is to understand the key parameters influencing AM 17-4 PH steel fatigue life under ULCF conditions and to develop simple predictive models for fatigue-life estimation in AM 17-4 steel components. In this study, both AM and traditionally produced (wrought) material samples are fatigue tested under fully reversed (R = −1) strain controlled (2–4% strain) loading and characterized using micro-hardness, x-ray diffraction, and fractography methods. Results indicate decreased fatigue life for AM specimens as compared to wrought 17-4 PH specimens due to fabrication porosity and un-melted particle defect regions which provide a mechanism for internal fracture initiation. Heat treatment processes performed in this work, to both the AM and wrought specimens, had no observable effect on ULCF behavior. Result comparisons with an existing fatigue prediction model (the Coffin–Manson universal slopes equation) demonstrated consistent over-prediction of fatigue life at applied strain amplitudes greater than 3%, likely due to inherent AM fabrication defects. An alternative empirical ULCF capacity equation is proposed herein to aid future fatigue estimations in AM 17-4 PH stainless steel components.