热压制备Mo-Nb-Si系新型高温金属硅化物合金.pdf

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2010年12月
Powder Metallurgy Technology
Dec.2010
制品
热压制备Mo-Nb-i系新型高温
金属硅化物合金
宋秋香”陈辉”马勤,2
1)(兰州理工大学甘肃省有色金属新材料省部共建国家重点实验室,兰州730050)
2)(兰州理工大学有色金属合金省部共建教育部重点实验室,兰州730050)
摘要:以Mo粉、Nb粉和i粉为原料,采用机械活化/热压工艺制备(Mo1-,Nb,)3Si3(x=0,0.4,0.6,1,0)
型高温金属硅化物。通过XRD、SEM和EDS等分析手段对合金试样进行物相分析、显微组织观察、微区成分
分析及力学性能测试。结果表明:合金试样的主要物相为Mo,Si3、a-Nb3Si3、y-Nb3Si,及其(Mo,Nb)Si1和B
(Nb,Mo)sSi3固溶体相,Mo有助于高温相B-N3Si3的相稳定;随着Nb含量的增加,硬度值呈上升趋势,合金
硬度较高,达1311.5~1397.5HV;试样的压痕断裂韧度和抗压强度呈先增加后降低的趋势,当x=0.6时断
裂韧度和抗压强度达到最大,分别为4.71MPa?m'和1637MPa,Nb,Siy和Nbss(Nb基固溶体)有助于合金
断裂切度的提高
关键词:金属硅化物;Mo3Si3;热压;断裂韧度
Preparation of MO-NB-SI system high-temperature metal
silicides by hot-pressing sintering process
Song Qiuxiang ,Chen Hui, Ma Qin
1)( State Key Laboratory of Gansu Advanced Non-ferrous Metal Materials, Lanzhou University of
Technology, Lanzhou 730050, China)
2)(Key Laboratory of Non-ferrous Metal Alloys, The Ministry of Education, Lanzhou University of
Technology, Lanzhou 730050, China
Abstract High-temperature metal silicide (MO-NB, )s,, (x=0, 0.4, 0.6, 1.0)was synthesized from element
Mo, Nb and Si powders by mechanical milling activation and hot-pressing sintering technology. The phase
composition, microstructure, micro-area component analysis and mechanical properties were investigated by XRD, SEM
and EDS etc. Results show that the main phases of these alloys are Mos Si, -Nb, Si,, y-nb, Si, and the solid solution
phase of(Mo, Nb )s Si, and 8-(Nb, Mo)s Si, A-NBS Si, is stabilized by adding Mo. With the content of Nb increasing
the hardness of the alloys increase to 1 311.5-1397.5 HV, the indentation fracture toughness and compressive
strength at first increase then decrease, when x=0. 6, the maximum indentation fracture toughness and compressive
strength is 4. 71 MPA.m"and 1 637 Mpa respectively. Nb, Si, and Nbss contribute to the improvement of fracture
toughness of alloys
Key words: metal silicide; Mos Si, hot-pressing; fracture toughness
随着航空、航天技术的不断发展,对高温结构材材料难以在苛刻条件下长期服役-2。Mo-Si系过
料工作温度和高温性能的要求越来越高,传统高温渡金属硅化物Mo,Si3具有高的熔点、硬度和弹性模
甘肃省自然科学基金资助项目(3ZS061-A25-038
*宋秋香(1980-),在读硕士。E-mail: chenhui002@q,com
收稿日期:2009-09-07