热暴露对Cr-12Nb-4.4Ni合金组织及性能的影响  

Effect of Thermal Exposure on Microstructure and Properties of Cr-12Nb-4.4Ni Alloy

作　　者：邓莉萍[1,2] 霍俊宏 鲁世强[1,2] 汤斌兵 Deng Liping;Huo Junhong;Lu Shiqiang;Tang Binbing(Nanchang Hangkong University,Nanchang 330063,China;Nanjing University of Aeronautics and Astronautics,Nanjing 210016,China;Nanchang University,Nanchang 330031,China)

机构地区：[1]南昌航空大学,江西南昌330063 [2]南京航空航天大学,江苏南京210016 [3]南昌大学,江西南昌330031

出　　处：《稀有金属材料与工程》2019年第12期4068-4073,共6页Rare Metal Materials and Engineering

基　　金：国家自然科学基金（51074092）;江西省自然科学基金（20161BAB206113）;江西省教育厅落地计划项目（KJLD14056）;江西省教育厅科技计划（GJJ160677）

摘　　要：对机械合金化+热压制备的Cr-12Nb-4.4Ni合金在1200℃下分别热暴露30,50,100 h,研究了热暴露不同时间后合金的组织和性能的变化。结果表明:合金由Cr固溶体和NbCr2构成,Ni主要存在于NbCr2中,热暴露过程中物相稳定;随着热暴露时间的延长,合金中Cr固溶体颗粒长大而NbCr2颗粒尺寸变化不大,Ni优先取代Cr的位置,松弛了NbCr2结构,Cr/NbCr2两相界面处压应力的增加,促进了Cr固溶体中位错的出现和NbCr2颗粒中层错/孪晶密度的增加。随着热暴露时间的延长,合金的室温抗压强度,屈服强度和塑性应变虽略有降低,但仍能保持较高的强度和良好的塑性,热暴露100 h后,其抗压强度,屈服强度和塑性应变仍有2170 MPa,1406 MPa和9.5%。Cr-12Nb-4.4Ni合金热暴露100 h后仍具有良好的断裂韧性。The Cr-12 Nb-4.4 Ni alloy, prepared by mechanical alloying and hot pressing, was thermally exposed at 1200 °C for 30, 50 and 100 h. Then, the microstructure and properties of the thermally exposed Cr-12 Nb-4.4 Ni alloy were studied. The results show that the phase constituent is stable during the thermal exposure process. It consists of Cr solid solution(Crss) and NbCr2, and Ni is mainly presented in NbCr2. The grain size of Crss increases with the increase of thermal exposure time, while the grain size of NbCr2 particle has no obvious change. The NbCr2 structure becomes loose due to the replacement of Cr by Ni. The increase of compressive stress in the phase interface of Cr/NbCr2 promotes the emergence of dislocations in Cr matrix and the increase of stacking fault/twinning fault in NbCr2 particles. With the thermal exposure time increasing, the compressive strength, yield strength and plastic strain of the Cr-12 Nb-4.4 Ni alloy decrease slightly while the alloy still remains relatively high room temperature strength and good plastic during the thermal exposure process. After thermal exposure for 100 h, the compressive strength, yield strength and plastic strain are 2170 MPa, 1406 MPa and 9.5%, respectively. The Cr-12 Nb-4.4 Ni alloy can keep good fracture toughness after thermal exposure for 100 h.

关 键 词：Cr基合金 LAVES相 热暴露 NI 晶体缺陷 

分 类 号：TG144[一般工业技术—材料科学与工程]