激光沉积贝氏体/马氏体复相超高强钢组织性能研究  

Microstructural and Mechanical Properties of Laser⁃Deposited Bainite/Martensite Complex Phase Ultra⁃High Strength Steel

作　　者：唐延川 张锦锋 沈明学 焦海涛 刘德佳[1,2] 唐兴昌 Tang Yanchuan;Zhang Jinfeng;Shen Mingxue;Jiao Haitao;Liu Dejia;Tang Xingchang(State Key Laboratory of Performance Monitoring and Protecting of Rail Transit Infrastructure,East China Jiaotong University,Nanchang 330013,Jiangxi,China;School of Materials Science and Engineering,East China Jiaotong University,Nanchang 330013,Jiangxi,China;State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals,Lanzhou University of Technology,Lanzhou 730050,Gansu,China;School of Materials Science and Engineering,Lanzhou University of Technology,Lanzhou 730050,Gansu,China)

机构地区：[1]华东交通大学轨道交通基础设施性能监测与保障国家重点实验室,江西南昌330013 [2]华东交通大学材料科学与工程学院,江西南昌330013 [3]兰州理工大学省部共建有色金属先进加工与再利用国家重点实验室,甘肃兰州730050 [4]兰州理工大学材料科学与工程学院,甘肃兰州730050

出　　处：《中国激光》2024年第24期47-61,共15页Chinese Journal of Lasers

基　　金：国家自然科学基金(52065023,52061022);江西省自然科学基金(20232BAB204009,20202ACBL214015)。

摘　　要：随着重载列车运速和轴重的不断提升,重载钢轨的表面损伤日益加剧。利用激光沉积技术结合预热手段对温度场进行控制,制备超高强钢修复层,分析不同热循环历程下,钢中贝氏体/马氏体组织的相对比例、亚结构特征及力学性能的演变规律。激光沉积态的试验钢显微组织以马氏体为主,而在预热态显微组织中出现大量贝氏体,随着预热温度由280℃上升至320℃,试验钢显微组织中贝氏体的比例由47.9%上升至62.5%,贝氏体呈现出板条状和片状混合的形貌,板条束尺寸明显细化(由13.5μm减小至8.5μm)。激光沉积态的试验钢具有较高的抗拉强度(1501 MPa),但伸长率较低(仅为6.8%);经过预热处理后,试验钢在仅损失少量抗拉强度(10%以内)的条件下,塑性得到显著改善,其在320℃预热态下的伸长率可较沉积态提高57.4%。Objective With the continuous increase in speed and axle load of heavy haul trains,the deterioration of bainitic steel rails is exacerbating,posing serious safety risks to railway transportation.The prompt resolution of surface damage repair issues of bainitic steel rails is imperative.While surface additive manufacturing repair methods such as laser deposition are suitable for damages of various sizes and exhibit good bonding between the repair layer and base material,they tend to form a large amount of brittle martensite structure in the repair layer and heat-affected zone.By employing preheating treatment temperature field control methods before laser deposition,the formation of martensite during the laser deposition process can be hindered.Combined with subsequent isothermal heat treatment,a repair layer primarily consisting of bainitic structure can be achieved,potentially leading to high-quality,cost-effective,and efficient surface repair of bainitic steel rails.This study systematically investigated the microstructural evolution and mechanical properties of laser-deposited ultra-high-strength steel repair layers under different temperature field conditions(laser deposition state,preheated at 280℃and 320℃),The focus was on analyzing the effects of different laser deposition thermal cycling processes on the relative proportions of bainite/martensite structures and substructural characteristics in laser-deposited ultra-highstrength steel,to elucidate the relationship between microstructural features and mechanical properties.These research findings have certain guiding significance for practical applications of laser deposition in heavy-haul steel rail repairs.Methods Utilizing laser deposition technology,a test steel repair layer is fabricated on the 30CrMnSiA medium carbon alloy steel substrate,using the compositions of the substrate and test steel detailed in Table 1.A constant-temperature preheating stage is positioned beneath the substrate(as shown in Fig.1)to maintain the temperature of the substrat

关 键 词：激光沉积 贝氏体 马氏体 复相钢 力学性能 

分 类 号：TG142.1[一般工业技术—材料科学与工程] TG665[金属学及工艺—金属材料]