Recent development of thermally assisted surface hardening techniques: A review
Recent development of thermally assisted surface hardening techniques: A review
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DOI：
10.1016/j.aime.2020.100006
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发表时间：
2021-05
期刊：
影响因子：
--
通讯作者：
Jun Liu;Chang Ye;Yalin Dong
中科院分区：
文献类型：
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作者：
Jun Liu;Chang Ye;Yalin Dong
热辅助表面强化技术使研究和工业应用激增，重点是强化具有高加工硬化、高强度和/或较差变形能力的金属材料。本文综述了常用的热辅助表面强化技术的发展，包括温喷丸强化、温激光冲击强化和热辅助超声表面强化。讨论了每种技术的发展和工作原理。对其力学性能的提高及其机理进行了详细的综述。与传统的表面强化技术相比，具有最佳加工温度的热辅助表面强化技术可以进一步提高机械零件的表面和亚表面硬度、硬化层厚度、疲劳寿命和耐磨性。这些改进归因于热能和高应变率塑性变形的协同作用所形成的独特的微观组织。热能可以软化材料，允许塑性变形产生更高的幅度和更深的加工硬化区域。更有趣的是，形变处理还会导致某些金属合金的动态应变时效和动态析出，从而导致析出强化，提高位错的稳定性和压缩残余应力。热-动力耦合效应为合金硬化提供了更广阔的设计空间。最后，对热辅助表面强化技术的研究方向进行了展望。
Thermally assisted surface hardening techniques have led to a surge in research efforts and industrial applications, with emphasis on strengthening of metallic materials with high work hardening, high strength and/or poor deformability. This paper reviews the development of common thermally assisted surface hardening techniques, including warm shot peening, warm laser shock peening, and thermally assisted ultrasonic surface hardening. The development and working principle for each of the techniques are discussed. The enhanced mechanical properties and corresponding mechanisms are reviewed in detail. As compared with conventional surface hardening techniques, thermally assisted surface hardening techniques with optimum processing temperatures can further increase the surface and subsurface hardness, thickness of the hardening layer, fatigue life, and wear resistance of mechanical components. The improvements are attributed to the unique microstructures fabricated by the synergistic effects of thermal energy and high-strain-rate plastic deformation. Thermal energy can soften the materials, allowing plastic deformation to produce higher magnitude and deeper region of work hardening. More interestingly, the thermomechanical treatment can also induce dynamic strain aging and dynamic precipitation in some metallic alloys, which leads to precipitation strengthening and enhanced stability of dislocations and compressive residual stress. The coupled thermal-dynamic effect enables a broader design space for alloy hardening. Lastly, future research directions of thermally assisted surface hardening techniques are discussed.