引用本文:吕艳红，张启富，吴子健.超音速火焰喷涂CoCrW涂层热震过程中的裂纹扩展行为[J].中国表面工程,2015,28(6):81~87
LV Yanhong, ZHANG Qifu, WU Zijian.Extended Behavior of Crack During Thermal Shock Testing of HVOF Sprayed CoCrW Coatings[J].China Surface Engineering,2015,28(6):81~87
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超音速火焰喷涂CoCrW涂层热震过程中的裂纹扩展行为
吕艳红，张启富，吴子健
中国钢研科技集团有限公司 新冶高科技集团有限公司
摘要:
为研究CoCrW涂层的抗冷热冲击性能，采用JP5000型超音速火焰喷涂设备在高温合金表面制备了该涂层，分析了裂纹在热震过程中的扩展行为。结果表明，在800 ℃保温，25 ℃水淬的热循环条件下，经过40次热震后，涂层表面均匀地分布着网状裂纹，截面上存在垂直裂纹，但未出现涂层脱落现象；在裂纹与基体、涂层界面交汇处生成了弥散分布的以Al2O3为主要成分的氧化物。分析认为，热应力和组织应力是裂纹产生和扩展的主要驱动力，但裂纹吸收了热震过程中产生的能量，避免了应力集中，有利于提高涂层的抗热震性能。界面处弥散分布的氧化物降低了涂层与基体的结合强度，热震试验最终的失效形式可能是界面处涂层的剥离。
关键词:  超音速火焰喷涂  CoCrW涂层  抗热震性  裂纹扩展
DOI：10.11933/j.issn.1007-9289.2015.06.011
分类号:
基金项目:
Extended Behavior of Crack During Thermal Shock Testing of HVOF Sprayed CoCrW Coatings
LV Yanhong, ZHANG Qifu, WU Zijian
New Metallurgical Technology Co., Ltd., China Iron & Steel Research Institute Group
Abstract:
To study the thermal shock resistance，the CoCrW coatings were prepared by using the JP5000 HVOF equipment, and the extended behavior of cracks during the thermal shock test under 800 ℃ high temperature holding and water quenching at 25 ℃ was analyzed. The results show that after 40 times’ thermal cycles there are net cracks evenly distributed around the surface and vertical cracks in the cross section but no delaminating phenomenon on the coating; there exists the main oxide Al2O3 near the interface of substrate, coating and cracks. Thermal stress and transformation stress are analyzed to be the main driving forces for crack growth and propagation, however, the crack absorbed the energy produced during the thermal shock and avoids the stress concentration in the coating, which can be favor of improving thermal shock resistance of the coating.The discretely distributed Al2O3 decreases the adhesion strength between the coating and the substrate, and the final failure mode of the thermal shock may be the delamination of the coating at the interface.
Key words:  high velocity oxygen fuel(HVOF)  CoCrW coating  thermal shock resistance  crack propagation
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