高克玮
,
王燕斌
,
褚武扬
,
肖纪美
金属学报
研究了TiAl金属间化合物的组织结构和氢化物含量对屈服强度σ_(ys),解理断裂强度σ_F以及断裂韧性K_(Ic)的影响.结果表明,对单相γ,随等轴晶粒尺寸降低,σ_(ys)和σ_F略有升高,如出现层状结构(α+γ2两相),则σ_(ys),σ_F和K_(Ic)明显上升,氢化物使σ_(ys)上升但使K_(Ic)下降,层状结构的氢脆敏感性要比等轴γ的小. 合金中解理裂纹形核的阻力随着裂纹的扩展而不断增大,呈现稳态扩展,跟踪裂纹的形核和扩展,发现当裂尖塑性区及其变形量发展到临界值后,解理裂纹在塑性区中沿滑移带形核。
关键词:
TiAl
,
K_(Ic)
,
microstructure
,
hydride
M.Morinaga and H. Yukawa Department of Materials Science and Engineering
,
Graduate School of Engineering
,
Nagoya University
,
Furo-cho
,
Chikusa-ku
,
Nagoya 464-8603
,
Japan
金属学报(英文版)
The electronic structures are calculated by the DV-Xa molecular orbital method employing small model clusters in order to clarify the roles of the hydride forming elements, A, (e.g., La, Zr Ti, Mg) and non-forming elements, B, (e.g., Ni, Mn, Fe) in hydrogen storage alloys. It is confirmed from this calculation that hydrogen interacts more strongly with hydride non-forming elements, B, than hydride forming elements, A, in agreement with our previous calculations. However,the B-H interaction is enhanced only when some A element exists in the neighborhood. Otherwise, such a B-H interaction never operates in the alloy. In this sense,the coexistence of A and B elements are essential in the constitution of hydrogen storage alloys. Also, it is shown that the A/B compositional ratio of hydrogen storage alloys is understood in terms of a simple parameter, 2Bo(A - B) / /Bo(A - A)+ Bo(B-B)], where the Bo(A-B), Bo(A-A) and the Bo(B-B) are the bond strengths between atoms given in the parentheses.
关键词:
electronic structure
,
null
,
null
,
null
,
null
,
null
,
null
李瑞文
,
汪小琳
稀有金属材料与工程
为了探讨U-2.5％Nb(质量分数)合金的氢腐蚀行为,利用在线显微镜研究了U-2.5％Nb合金氢蚀初期氢化物的生长动力学,研究了U-2.5％Nb合金氢化初期的氢化物形貌、生长速度、氢化反应速度等之间关系.结果表明,利用在线显微镜表征氢化物的生长速度是可行的,氢化物前沿推进距离与时间呈线性关系.在一定温度范围内,氢化物的生长速度与反应温度符合Arrhenius关系,U-2.5％Nb合金氢化物生长激活能为24.34 kJ/mol.当温度增加到125℃附近时,氢化物的生长速度达到最大值,之后,随着反应温度的升高,生长速度快速下降.
关键词:
U-2.5％Nb
,
氢化物
,
生长动力学
