摘要
采用粉末冶金法制备以H13钢为基体,Cr2C3为硬质相及CaF2为固体润滑剂的高温自润滑热锻模具材料。分别观察H13钢、H13-Cr2C3和H13-Cr2C3-CaF2共3种烧结试样表面产生的裂纹及其生长情况,对比分析复合材料的热疲劳性能。通过20~600℃冷热循环100和200次实验发现:在交变热应力的作用下,裂纹优先在预制裂口处呈尖端状萌生,裂纹周围出现不同程度的氧化腐蚀。烧结试样孔隙大小、氧化物团聚和冷热循环内外温差使得裂纹以网状形式扩展,预制裂口的应力集中处热疲劳裂纹萌生扩展情况更为严重。硬质相Cr2C3有助于缓解材料的氧化腐蚀,润滑相CaF2析出后与基体和硬质相发生分离,促进氧化且分布在裂纹周围。H13-Cr2C3-CaF2复合材料的热疲劳性能低于纯H13钢和H13-Cr2C3材料。
High-temperature self-lubricating hot forging die material with H13 steel as the matrix,Cr2 C3 as the hard phase and Ca F2 as the solid lubricant was prepared by powder metallurgy method.The cracks and its growth on the surface of three sintered samples of H13 steel,H13-Cr2 C3 and H13-Cr2 C3-Ca F2 were observed respectively,and the thermal fatigue properties of the composite were compared and analyzed.Through 100 and 200 times cold and hot cycling tests at 20-600℃,it is found that under the alternating thermal stress,the sharp end-shape cracks preferentially germinate at the preformed notches and oxidative corrosion in varying degrees occurs around the cracks.The cracks to expand in mesh type caused by pore size of sintered sample,the oxide agglomeration and the temperature difference between the inside and outside in the hot and cold cycle.Thermal fatigue crack germination and propagation at the stress concentration of prefabricated cracks are more serious.The hard phase Cr2 C3 is helpful to alleviate the oxidative corrosion of the material,the lubricating phase Ca F2 separates from the matrix and the hard phase after precipitation,which promotes the oxidation and distributes around cracks.The thermal fatigue properties of H13-Cr2 C3-Ca F2 composite is lower than that of pure H13 steel and H13-Cr2 C3 material.
作者
蒋骋
王华君
姚振华
李梦璐
刘清阳
JIANG Cheng;WANG Hua-jun;YAO Zhen-hua;LI Meng-lu;LIU Qing-yang(School of Materials Science and Engineering,Wuhan University of Technology,Wuhan 430070,China;Hubei Engineering Research Center for Green Precision Material Forming,Wuhan 430070,China)
出处
《塑性工程学报》
CAS
CSCD
北大核心
2021年第1期189-195,共7页
Journal of Plasticity Engineering
基金
武汉理工大学优秀学位论文培育项目(2017-YS-006)。
关键词
H13钢
热疲劳
裂纹萌发
粉末冶金
自润滑材料
H13 steel
thermal fatigue
crack germination
powder metallurgy
self-lubricating material
