Sheng Li
,
Yu-Zeng Chen
,
Yu-Ke Cao
,
Feng Liu
金属学报(英文版)
doi:10.1007/s40195-016-0367-4
It is well known that, in kinetics, the interaction between dislocations and interstitial solute normally exerts strong solute drag effect on dislocations, leading to strong solution hardening of the metals. However, due to the low mobility of interstitial solute in many metals, thermodynamic aspect of the interaction between dislocations and interstitial solute is often unobservable and omitted. It will be shown in this article by reviewing the H-induced behaviors in metal-H systems, especially the recent progress in Pd-H system that, when the interstitial solute atoms are highly mobile and able to collect in the vicinity of mobile dislocations easily, the scenario will be remarkably different. The interaction between dislocations and these highly mobile interstitial solute atoms, in thermodynamics, will reduce the line energy of dislocations and will facilitate the generation of dislocations, leading to an increase in dislocation density and an enhanced strain hardening of metals upon plastic deformation.
关键词:
Plastic
,
deformation
,
Dislocation
,
Interstitial
,
solute
,
Strengthening
,
mechanism
,
Thermodynamics
Ji-Juan Liu
,
Ran Li
,
Lian-Xiang Fang
,
Ju Wang
,
Tao Zhang
金属学报(英文版)
doi:10.1007/s40195-016-0368-3
Unexpected facture without any room-temperature plasticity severely limits potential structural applications of bulk metallic glasses (BMGs), especially La-, Mg- and Fe-based ones. In this study, a simple free corrosion method was provided to improve the plasticity of a brittle (La, Ce)-based BMG by the introduction of high-density corrosion defects on the surface. The influences of immersing time in 0.1 mol/L H2SO4 aqueous solution on the surface morphology and mechanical properties of the BMG were evaluated. With increasing immersing time from 5 to 30 min, the degree of surface corrosion increased obviously, and the distribution of corrosion defects became more homogenous. In the samples, the yielding phenomenon and certain plasticity appeared up to 0.3% after the surface treatment. The yielding and plasticity can be attributed to easier nucleation of shear bands on the defect surface rather than on the glabrous surface. The results provided a novel method to improve the plasticity of BMGs.
关键词:
Metallic
,
glasses
,
Corrosion
,
plastic
,
deformation
,
mechanism
,
Rapid
,
solidification
,
Microstructure
Ming-Zhen Wei
,
Zhen-Hua Cao
,
Xiang-Kang Meng
金属学报(英文版)
doi:10.1007/s40195-016-0377-2
In this work, we have investigated the mechanical properties of Cu/Ta, Ag/Cu and Ag/Nb multilayers with different heterogeneous interfaces. The results suggest that when individual layer thickness (h) is larger than 5-10 nm, the hardness/strength of three different multilayer systems has the similar length scale effect with decreasing layer thickness, while when h ≤ 5 nm, the three multilayer systems show remarkably different plastic deformation behaviors. The strength curves exhibit the variation trends of unchanging, softening and increasing corresponding to Cu/Ta, Ag/Cu and Ag/Nb multilayers, respectively. The microstructure analysis shows that three kinds of multilayers have totally different interfacial structures, which lead to the different strengthening or softening mechanisms.
关键词:
Metallic
,
multilayers
,
Plastic
,
deformation
,
Interfacial
,
structures
,
Strengthening
,
mechanism
金强
,
方鸿生
,
曹建军
,
郑燕康
,
陈秀云
金属学报
采用透射电镜技术研究高碳钢下贝氏体铁素体与母相奥氏体界面结构,发现铁素体宽面上存在可移动的生长台阶、巨型台阶以及它们的三维形态;在下贝氏体铁素体宽面上还存在结构台阶,生长台阶也可以由结构台阶演变而来,为下贝氏体的台阶生长机制提供了实验证据。
关键词:
贝氏体铁素体
,
mechanism
,
broad face
,
null
邱于兵
,
郭稚弧
,
林汉同
中国腐蚀与防护学报
在3％NaCl、006％NaCl和自来水3种实验介质中，研究了Q 235钢的方波脉冲电流幅值(I\-A)、频率(f)和占空比(P)的变化对于阴极极化 电位(E)和极化幅度(ΔE)的影响规律.结果表明，E和ΔE随方波I\-A 、f和P的增加而变负，但当E接近或负于-100 V(SCE)时，再增加各电流参数的值， E和ΔE的负移程度都大大减小.各电流参数对ΔE的影响程度不同，并与E值 密切 相关.提出调整电流参数总的原则和方法是：在达到所要求的保护效果的前提下，尽可能采 用低P、低IA的电流参数，并优先调整f,再调整I\-A.
关键词:
电流参数
,
square wave
,
pulsed current
,
cathodic protection
,
mechanism
,
null
