Z.F. Peng
,
Y Y Ren
,
B.Z. Fan
,
J. W Qin
,
P. Yan
,
J. C. Zhao
,
Y Q. Wang and J.H. Sun (Wuhan University of Hydraulic and Electric Engineering
,
Wuhan 430072
,
China)(Central Iron and Steel Research Institute
,
Beijing 100081
,
China)
金属学报(英文版)
Prolonged tension tcsts were caTried out by comblning elevated temperatures with declined stresses over thc range of 760-1050° C and 780-115MPa. The effects of temperature and applied stress on rupture life, and the relations of temperuture, applied stress and mpture life to characteristic dimensions of coherent phases (γ matrix channel width and mpcd γ precipitate thickness), and to the elongation as well as to the cross sectional area reduction of thc tested specimens were investigated. Under all testing conditions, longittLdinal coalescence of seveml adjacent armys of γ precipitates could occur to dtherent extents along the direction of the applied stress axis in addition to their normal directional coarsening. The extent of γ Longitudinal coalescence became increased and its morphology tended to be irmpular with the increase of temperuture although the applied stresses were relatively lower.
关键词:
superalloy CMSX-2
,
null
,
null
,
null
鲁二敬
,
卢峰华
,
许鸿吉
,
谢明
,
钮旭晶
机械工程材料
通过周期浸润腐蚀试验，对比研究了S355．12W耐候钢和Q345R低合金钢在NariSOs溶液中的耐腐蚀性能，并用扫描电镜对腐蚀产物进行了观察和分析。结果表明：在相同试验条件下，S355J2W耐候钢的腐蚀速率低于Q345R钢的；S355J2W耐候钢会在表面形成黑褐色锈层，而Q345R钢表面形成橘红色易剥落的疏松锈层；S355J2W耐候钢腐蚀产物微观形貌为沿放射性方向生长的针状晶体，Q345R钢为颗粒状聚合物堆积而成，形状无规则，颗粒之间有较大的空隙。
关键词:
S355J2W耐候钢
,
周期浸润腐蚀试验
,
耐腐蚀性能
谷晓鹏
,
段珍珍
,
邓钢
,
谷晓燕
材料工程
doi:10.11868/j.issn.1001-4381.2015.02.004
利用激光-MAG复合焊和MAG焊进行了厚板S355J2W+N低碳钢的焊接实验,分析了两种焊接方法接头的微观组织和力学性能.结果表明:复合焊和MAG焊焊缝接头均由焊缝区、过热区、重结晶区和不完全重结晶区构成,复合焊接头截面呈“高脚杯”状特点,焊缝填充量和热影响区宽度较MAG焊明显减小.复合焊由于冷却速率快,过热区魏氏组织略有增多,硬度高于MAG焊,抗拉强度和弯曲性能与MAG焊相比,无显著差异,均能够满足生产标准的要求.
关键词:
S355J2W+N
,
激光
,
MAG
,
复合焊
,
接头组织
,
性能
Journal of Materials Research
The morphology of the dark and bright regions observed by transmission electron microscopy for the Zr(64.13)Cu(15.75)Ni(10.12)Al(10) bulk metallic glass strongly depends on the ion beam parameters used for ion milling. This indicates that the ion beam could introduce surface fluctuation to metallic glasses during ion milling.
关键词:
room-temperature
Journal of Physics-Condensed Matter
The temperature dependences of the magnetization, internal energy and specific heat in a three-sublattice ferrimagnet or ferromagnet with /J(ab)/ = /J(bc)/ not equal /J(ca)/ are calculated within the framework of the linear spin-wave approximation, by employing retarded Green's functions. For both the ferromagnet and the ferrimagnet, the internal energy and the specific heat decrease with increasing J ' /J and/or the value of the spins. For fixed values of S,, Sb, S, and J ' /J, the internal energy and the specific heat increase, whereas the sublattice magnetization decreases with increasing temperature theta. The three-sublattice ferrimagnet has some particular characteristics which are not shown by the systems with two sublattices. For ferrimagnets, the antiferromagnetism of the system becomes weaker with increasing J ' /J. The sublattice magnetization at low temperatures (also the magnetization M(0) at 0 K) of a ferrimagnet increases with increasing J ' /J for fixed values of S(a), S(b) and S(c). The effects of the spins S(a) (S,) and Sb On the magnetizations of other sublattices differ. The characteristics of the a-sublattice are the same as those of the c-sublattice, due to their similarity as well as the symmetry of the system. The behaviours of the b-sublattice are different from those of the a- and c-sublattices, due to the asymmetry of the three-sublattice system. The spin-value dependences of the spin deviation Deltam per spin land also the energy for the zero-point quantum fluctuation) of the system are different for different sublattices. These differences are ascribed to the asymmetry of the three-sublattice systems, which leads to the new intrinsic properties of the systems.
关键词:
layered heisenberg ferrimagnets;spin-wave theory;elementary;excitations;superlattices;systems;magnetoresistance;antiferromagnet;interfaces
Physical Review B
The Hamiltonian for a four-sublattice Heisenberg ferrimagnet or ferromagnet with different exchange constants (J(ab) = J(cd) not equal J(bc) = J(da)) was established. An extended Bogoliubov transformation was developed by solving an equation group, consisting of 20 equations and 20 unknowns. The procedure for solving the equation group was carried out by introducing a simple way of reducing the numbers of the equations and the unknowns. The spin-wave spectra in the present system have been determined by performing the standard Holstein-Primakoff transformation and the Bogoliubov one. It has been found that the spin-wave spectra of the present system depend on the exchange constants and that the degeneracy of the spin-wave spectra remains. The results for a special case (J(ab) = J(bc)) i.e., an antiferromagnet are discussed briefly. The spin-wave spectra of the four-sublattice Heisenberg antiferromagnet are found to be degenerative also and they are linear in k for small k.
关键词:
model
金属学报
J积分的临界值J_(Ic)(张开型)目前被广泛用作中低强度钢的断裂准则.根据线弹性断裂力学理论和弹塑性断裂力学的实验规律,现提出一个新的J积分和应变能间的关系式:J=2/B(W-α)[U—U_o+(M~2ψ)/(BE′W~2)],其中ψ与跨距S/W和裂纹深度α/W有关·此式对于跨距和裂纹深度没有限制,因而作为弯曲试样的J积分计算公式,具有较为广泛的适用范围·当α/W=0时,J=0,从物理意义上看也比较合理,为了便利计算,并列出ψ值表,可以查找。
关键词:
Doris Smith
,
Ken Lynam
环境化学
本文中使用安捷伦SPEC C18AR固相萃取膜盘成功萃取了水中的有机氯农药残留和除草剂.使用双柱配置的GC/μECD系统进行检测,安捷伦J&W DB-35ms UI超高惰性色谱柱作为分析柱,DB-XLB色谱柱为确认柱.该方法为浓度接近或低于最大污染限值的含氯有机物提供了高度灵敏的分析方法.根据预估的分析物萃取浓度,方法使用的校准范围为1-100 ng· mL-1.分别对0.01 μg·L-1的加标水样和一个自来水水样进行了萃取和分析,结果证明可满足水中的有机氯农药残留和除草剂的测定.
关键词:
有机氯农药
,
除草剂
,
色谱柱
陈篪
金属学报
<正> 目前,J_(Ⅰc)的测试引起了国内外的厂泛重视。三点弯曲试样得到了最广泛的应用。我们曾导出 J=(2U/B(W-a) (1)的关系,式中U是试样的应变能。Rice等在[2]中所建议的是另一关系 J=2/(B(W-a)integral from n=0 to △aPd△_a (2)其中 △_a=△-△_0 (3)△_0是同尺寸的无裂纹试样加载到同一载荷P时的位移。(1)和(2)式虽形式相近但内容不同究竟何者更为正确,很有必要加以澄清。 我们的推导是以U=B(W-a)~2f(△)或其等效关系P=B(W-a)~2φ(△)为出发点的,这里不再重复。Rice则假定
关键词:
