热处理对深海耐压壳用Ti542222钛合金厚板组织性能影响研究  

Microstructure and Properties of High Strength and High Toughness Titanium Alloy Plate for Deep-Sea Pressure Hull with Solution Aging

作　　者：海敏娜 王永梅[1] 贾栓孝[1] 黄帆 严学波[2] 李芳婷 Hai Minna;Wang Yongmei;Jia Shuanxiao;Huang Fan;Yan Xuebo;Li Fangting(Baoji Titanium Industry Co.,LTD.,Baoji 721013,China;Baoti Group Co.,LTD.,Baoji 721014,China)

机构地区：[1]宝鸡钛业股份有限公司,陕西宝鸡721013 [2]宝钛集团有限公司,陕西宝鸡721014

出　　处：《稀有金属》2023年第3期365-372,共8页Chinese Journal of Rare Metals

基　　金：国家重点研发计划项目(2016YFC0304202,2016YFC0304205,2019YFC0311503)资助。

摘　　要：为获得强度-塑性-韧性最佳匹配的深海耐压壳用Ti542222高强高韧钛合金,研究了固溶温度、时效温度对Ti542222厚板显微组织、力学性能和断口形貌的影响。结果表明:经750~800℃固溶处理后,合金由初生α_(p)相和亚稳β相组成,且均随温度升高而长大,β基体上次生α_(s)相发生了由α_(s)→β的转变,强度降低,韧性提高;当在800~860℃固溶处理时,初生α_(p)相减少,在β相基体上析出斜方马氏体α″相,且随温度升高,初生α_(p)相和β相逐渐粗化,α″相大量增加,强度稳步提升,塑、韧性降低;在860℃/1.5 h空冷(AC)+(550~760)℃/4 h AC固溶时效中,当时效温度为550℃时,显微组织与860℃/1.5 h AC退火后基本一致,亚稳β相分解形成的次生α_(s)相比较细小、均匀,强度仍保持高值,但韧性不能满足深海耐压壳材料需求,当时效温度为630~760℃时,显微组织为初生α_(p)相、β相、α_(s)相,且随着时效温度升高,初生α相逐渐集聚长大,β相和α_(s)相片层厚度粗化,强化效果下降,韧性显著提高,仅当时效温度为700℃时,抗拉强度为1134 MPa,屈服强度为1057 MPa,伸长率为17.5%,冲击功为48 J,可较好地满足深海耐压壳用材料指标要求。因此,确定深海耐压壳用Ti542222钛合金最佳强度-塑性-韧性匹配的热处理制度为(860℃/1.5 h AC)+(700℃/4 h AC)。In order to obtain Ti542222 high strength and high toughness titanium alloy for deep-sea pressure hull with the best match⁃ing of strength-plasticity-toughness,Ti542222 titanium alloy plate with a thickness of 40 mm developed by Baoji Titanium Industry Co.,Ltd.was selected as the research object in this paper.α+β→βphase transition temperature was 897℃.The plate was prepared by phase-inversion temperature(Tβ)+(30~50)℃heating and the deformation was 50%~80%.At the same time,according to the heat treatment test scheme designed by AMSH 81200-H-2014 titanium and titanium alloy heat treatment specification,the solid solution system was 750~880℃/1.5 h air cooling(AC).The solution aging system was 860℃/1.5 h AC+(550~760)℃/4 h AC.Axiovert 200MAT metallographic microscope(OM)was used to observe the microstructure of the alloy after hot rolling and heat treatment.JSM6480 scanning electron microscope(SEM)was used to detect and analyze the microstructure and tensile fracture of the solution treatment and solution aging treatment.The effects of solution temperature and aging temperature on microstructure,mechanical prop⁃erties and fracture morphology of Ti542222 titanium alloys thick plate were studied by room temperature tensile test and Charpy impact test using Instron5885 electronic universal testing machine and JNS-300 impact testing machine.The results showed that after ordinary annealing at 750~800℃,the alloy was composed of primaryα_(p) phase and metastableβphase,and both of them grow up with the in⁃crease of temperature.The secondaryα_(s) phase on theβmatrix changes fromα_(s) toβ,and with recovery and recrystallization,the strength decreased and the toughness increased.When annealed at 800~860℃,the primaryα_(p) phase decreased,andα″phase pre⁃cipitates onβphase matrix.With the increase of temperature,the primaryα_(p) phase andβphase gradually coarsened,andα″phase increased greatly,then the strength increased steadily,and the plasticity and toughness decreased.In the dual annea

关 键 词：高强高韧 钛合金 深海耐压壳 热处理 组织性能 

分 类 号：TG146.23[一般工业技术—材料科学与工程]