摘要
利用高速激光熔覆在2Cr13钢基体表面制备了Ni625合金涂层,并对涂层进行了激光重熔处理。采用粗糙度仪、光学显微镜(OM)、扫描电镜(SEM)、X射线衍射仪(XRD)、X射线残余应力仪、电化学工作站及盐雾试验等分析了激光重熔前后涂层的宏观形貌、微观组织、残余应力及耐蚀性能。结果表明:激光重熔后,涂层表面粗糙度降低到1.76μm,降幅达86%,熔覆层更趋致密且表面平整度提升明显;激光重熔后涂层近表面区域的树枝晶间距减小,晶粒明显细化,重熔后熔覆层中的物相不变,主要由γ-(Ni,Fe)韧性相、Cr_(2)Ni_(3)相及少量M_(23)C_(6)硬质相构成;重熔前后涂层表面均为压应力,重熔态涂层表面的残余压应力水平略有下降;重熔态涂层的自腐蚀电位比基体提高约0.243 V,比熔覆态涂层提高约0.121 V;基体、重熔前后涂层试样的容抗弧半径和阻抗模值依次增大;经过96 h盐雾腐蚀试验后,重熔态涂层的质量损失率与基体和熔覆态涂层相比分别降低了94.1%和66.8%;分析认为重熔态Ni625涂层耐蚀性的提高归因于激光重熔处理后涂层表面致密性的增加和晶粒的细化。
Ni625 alloy coating was prepared on the surface of 2 Cr13 steel substrate by high speed laser cladding,and then the coating was treated by laser remelting.Macro morphology,microstructure,residual stress and corrosion resistance of the coating before and after laser remelting were analyzed by means of roughness instrument,optical microscope(OM),scanning electron microscopy(SEM),X-ray diffraction(XRD),X-ray residual stress instrument,electrochemical workstation and salt spray test.The results show that the surface roughness of the coating is reduced to 1.76μm with the decline of 86%after laser remelting.The remelted coating turns to become more dense and the surface flatness can be improved significantly.After laser remelting,the dendrite spacing in the near surface region of the coating decreases and the grains are obviously refined.After remelting,the phase of the cladding coating remains unchanged,which is composed ofγ-(Ni,Fe)ductile phase,Cr_(2)Ni_(3) phase and a small amount of M_(23)C_(6) hard phase.The residual stress on the coating surface before and after remelting is compressive stress,and the stress level after remelting decreases slightly.The self-corrosion potential of the remelted coating is about 0.243 V and 0.121 V higher than that of the substrate and the cladding coating,respectively.The capacitive reactance arc radius and impedance modulus of the substrate and the coating samples before and after remelting increase in turn.After salt spray corrosion test for 96 h,the mass loss rate of the remelted coating is reduced by 94.1%and 66.8%respectively compared with that of the substrate and the cladded coating.The analysis shows that the improvement of corrosion resistance of the remelted Ni625 coating is attributed to the increase of surface compactness and grain refinement of the coating after laser remelting.
作者
刘明霞
李昭
畅庚榕
尹志福
张秀萍
LIU Ming-xia;LI Zhao;CHANG Geng-rong;YIN Zhi-fu;ZHANG Xiu-ping(Shaanxi Key Laboratory of Surface Engineering and Remanufacturing,Xi’an University,Xi’an 710065,China;Xi’an Key Laboratory of Prototyping and Optimization of Implantable Devices,Xi’an University,Xi’an 710065,China)
出处
《材料热处理学报》
CAS
CSCD
北大核心
2022年第8期153-160,共8页
Transactions of Materials and Heat Treatment
基金
国家自然科学基金青年基金项目(52101097)
陕西省自然科学基础研究计划项目(2022CGBX-13,2021JM-512,2021JQ-797)
陕西省教育厅科技项目(21JS035)
西安市科技计划项目(2020KJWL01,21XJZZ0069)
西安文理学院先进表面工程与装备延寿项目(XAWLKYTD013)
陕西省表面工程与再制造重点实验室开放基金(tywl2021-2)。
关键词
高速激光熔覆
激光重熔
微观组织
晶粒细化
残余应力
耐蚀性
high speed laser cladding
laser remelting
microstructure
grain refinement
residual stress
corrosion resistance
作者简介
刘明霞(1981-),女,副教授,博士,主要研究方向为金属材料表面强化,发表论文15篇,E-mail:liumingxial121@163.com。
