B.X. Zhou
,
M.Y. Yao
,
Z.K. Li
,
X.M. Wang
,
J. Zhou
,
C.S. Long
,
Q. Liu
材料科学技术（英文）
In order to optimize the microstructure and composition of N18 zirconium alloy (Zr–1Sn–0.35Nb–0.35Fe–0.1Cr, in mass fraction, %), which was developed in China in 1990s, the effect of microstructure and composition variation on the corrosion resistance of the N18 alloy has been investigated. The autoclave corrosion tests were carried out in super heated steam at 400 °C/10.3 MPa, in deionized water or lithiated water with 0.01 mol/L LiOH at 360 °C/18.6 MPa. The exposure time lasted for 300–550 days according to the test temperature. The results show that the microstructure with a fine and uniform distribution of second phase particles (SPPs), and the decrease of Sn content from 1% (in mass fraction, the same as follows) to 0.8% are of benefit to improving the corrosion resistance; It is detrimental to the corrosion resistance if no Cr addition. The addition of Nb content with upper limit (0.35%) is beneficial to improving the corrosion resistance. The addition of Cu less than 0.1% shows no remarkable influence upon the corrosion resistance for N18 alloy. Comparing the corrosion resistance of the optimized N18 with other commercial zirconium alloys, such as Zircaloy-4, ZIRLO, E635 and E110, the former shows superior corrosion resistance in all autoclave testing conditions mentioned above. Although the data of the corrosion resistance as fuel cladding for high burn-up has not been obtained yet, it is believed that the optimized N18 alloy is promising for the candidate of fuel cladding materials as high burn-up fuel assemblies. Based on the theory that the microstructural evolution of oxide layer during corrosion process will affect the corrosion resistance of zirconium alloys, the improvement of corrosion resistance of the N18 alloy by obtaining the microstructure with nano-size and uniform distribution of SPPs, and by decreasing the content of Sn and maintaining the content of Cr is discussed.
关键词:
Zirconium alloys
,
null
,
null
,
null
陈树东
,
项建明
,
王晓翠
,
洪笑
硅酸盐通报
以Ca(OH)2、SiO2、Fe2O3、Al2O3化学纯为原料,分别掺入不同质量分数的Ba(OH)2制备不同矿物相组成的熟料相,运用化学分析、XRD、SEM、水化热测试方法,研究掺Ba(OH)2后熟料相中硅酸三钙-硅酸二钙(C3S-C2S)混合相组成、晶型、新相生成的变化规律.结果表明:Ba(OH)2一定程度上削弱C3S形成,且稳定β-C2S形成效应明显,矿物相体系中α'-C2S、α-C2S量减少并转换为β-C2S,掺量大于2.5％后有新相Ba0.48 Ca1.52SiO4形成;Ba(OH)2掺入促使矿物相中C2S相明显增多,晶粒整体尺寸变小,边界变圆润;随Ba(OH)2掺量递增,熟料样的水化速率呈持续减小的趋势变化.
关键词:
C3S相
,
β-C2S
,
水化速率
,
水化
姜奉华
,
徐德龙
硅酸盐通报
doi:10.3969/j.issn.1001-1625.2004.06.006
通过研究Q相与C2S和Q相与C4AF的共存条件,构造Q相-C2S-C4AF水泥系统,对此系统水泥形成条件进行研究.研究表明:Q相与C2S和Q相与C4AF能够共存,可以组成Q相-C2S-C4AF-C12A7水泥系统.在Q相-C2S-C4AF-C12A7水泥系统中,Q相在1270℃开始生成,随着温度的升高,Q相的生成量逐渐增大;采用V2O5对β-C2S具有较好的稳定作用.随着C4AF量的增加,Q相的量也在增加,同时,烧成温度降低.
关键词:
Q相
,
Q相-C2S-C4AF水泥
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形成条件
,
抗压强度
管宗甫
硅酸盐通报
用工业原料在不同温度预合成C2S(2CaOSiO2)为主要矿物的前导物,并以该前导物为基础,补入适量的钙,在不同温度下二次烧成水泥熟料.结果显示:采用1250℃、1300℃和1350℃预合成的C2S前导物配料二次烧方法,有利于熟料在低温下烧成,在1350℃左右实验熟料样品中游离氧化钙即可小于1.0％.相应C3S在熟料体系中的表观形成活化能相比不同配料烧成的对比组明显降低,而不同温度制备的前导物配料,C3S在熟料体系中的形成活化能相差无几.
关键词:
C2S前导物
,
二次烧成
,
水泥熟料
,
硅酸三钙
,
活化能
Transactions of Nonferrous Metals Society of China
DZ40M is a newly developed directionally solidified Go-based superalloy. Its microstructural characteristics and mechanical properties at room and elevated temperatures after ageing for 100 similar to 1000 h at 850 degrees C were studied. The results showed that 100 h ageing at 850 degrees C results in a substantial increase of tensile strength at room temperature and stress-rupture life at elevated temperatures, serious decrease of ductility at room temperature and improvement for stress-rupture ductility. With increasing ageing time, stress-rupture life tends to decrease and the other properties keep at essential constant. During ageing, primary carbides M7C3 and MC decompose sluggishly, fine M23C6 precipitates copiously around them and M6C forms on the surface of some M7C3. The increased strength of the aged alloy is attributed to a strong interaction between M23C6 and dislocations.
关键词:
directional solidification;Co-based superalloy;long-term ageing;mechanical property
