摘要
为了提高H13模具钢的韧性和淬透性,延长使用寿命,在其表面激光熔覆了Stellite156钴基合金涂层。熔覆过程中,为了减少涂层气孔、细化组织晶粒和改善涂层的硬度以及耐磨性,制备了不同Y_(2)O_(3)含量(0、0.5%、1.5%、2.5%、3.5%)的Stellite156钴基合金涂层。利用金相显微镜分析涂层的形貌和气孔,利用SEM和XRD分析涂层的显微组织及物相组成,利用EDS分析涂层中合金元素的偏析情况,利用显微硬度计对涂层的硬度进行检测,最后利用摩擦磨损实验机测试涂层的耐磨性。分析实验结果发现:Y2O3含量对涂层的外观影响不大,较少的Y_(2)O_(3)含量可改善熔池的热对流,有效减少涂层中的气孔数量。Y_(2)O_(3)含量为2.5%时,涂层中气孔增加,涂层物相主要有Cr-Ni-Fe、Cr、Ni17W3及少量Y_(2)O_(3)和(Cr,Co,Ni)23C6;与未添加Y2O3的涂层相比,涂层晶粒度明显减小,晶粒排列更为细密整齐,涂层晶粒与晶界的成分偏析也明显改善。当Y_(2)O_(3)含量从0增加到2.5%时,涂层最大平均显微硬度HV值达到了560,高于基体的500;但当Y_(2)O_(3)含量继续增加到3.5%时,涂层硬度又明显减小,甚至低于未添加Y_(2)O_(3)的涂层硬度值。适量的Y_(2)O_(3)能够起到改善涂层气孔缺陷、细化晶粒、改善成分偏析以及提高涂层硬度的作用,进而提高涂层的耐磨性。
In order to improve the toughness and hardenability of H13 die steel,as well as prolong its service life,Stellite156 Co-based alloy coating was prepared on its surface by laser cladding.During the cladding process,in order to reduce the pores,refine the grain size and improve the hardness and wear resistance of the coating,Stellite156 Co-based alloy coatings with different Y2O3 contents(0,0.5%,1.5%,2.5%,3.5%)were prepared.The morphology and porosity of the coatings were analyzed by metallographic microscope,the microstructure and phase composition of the coatings were analyzed by SEM and XRD,the segregation of alloy elements in the coatings was analyzed by EDS,the hardness of the coatings was tested by microhardness tester,and the wear resistance of the coatings was tested by friction and wear tester.The experimental results reveals that Y_(2)O_(3) content has little effect on the appearance of the coating,and less Y_(2)O_(3) content can improve the heat convection in the molten pool and effectively reduce the number of pores in the coating.When Y_(2)O_(3) content is 2.5%,the pores in the coating increase,and the coating phases mainly include Cr-Ni-Fe,Cr,Ni17W3 and a small amount of Y_(2)O_(3) and(Cr,Co,Ni)23C6.Compared with the coating without Y_(2)O_(3),the grain size of the coating with 2.5% Y_(2)O_(3) is significantly reduced,the grain arrangement is more compact and orderly,and the composition segregation in crystal grains and grain boun-daries of the coating is also significantly improved.When the Y_(2)O_(3) content increases from 0 to 2.5%,the maximum average HV microhardness of the coatings reaches 560,which is higher than 500 of the substrate.However,when the Y2O3 content continues to increase to 3.5%,the hardness of the coating significantly decreases,even lower than that without Y_(2)O_(3).Therefore,a proper amount of Y_(2)O_(3) can improve the pore defects,refine the grains,improve the composition segregation,increase the hardness of the coating,and then improve the wear resistance of the coating.
作者
姚芳萍
房立金
李金华
冯伟龙
YAO Fang-ping;FANG Li-jin;LI Jin-hua;FENG Wei-long(School of Mechanical Engineering and Automation,Liaoning University of Technology,Jinzhou 121001,China;Faculty of Robot Science and Engineering,Northeastern University,Shenyang 110004,China)
出处
《稀有金属与硬质合金》
CAS
CSCD
北大核心
2021年第4期29-34,共6页
Rare Metals and Cemented Carbides
基金
辽宁省高等学校产业技术研究院项目(cyyjy2018011)
。
