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
杜林秀
,
熊明鲜
,
姚圣杰
,
刘相华
金属学报
以低碳微合金钢为对象, 提出了一种利用相变进行亚微米化的新方法. 通过大变形
量温变形和循环淬火相结合的方法, 使奥氏体晶粒细化到1—2 μm.
在一般冷速的连续冷却条件下, 得到的
铁素体粒径接近或超过原奥氏体晶粒; 若
冷却过程中在Ar3点以下施加较大的变形, 则可以获得尺寸为0.1—0.3 μm的亚微
米级铁素体组织. 大变形量的温变形使得原始
组织中的碳化物分布均匀, 促进了加热过
程中碳化物的溶解及超细奥氏体晶粒的形成；
晶界滑动促进奥氏体的晶界形核可能是超细奥氏体
形变诱导相变的主要机制.
关键词:
纳米晶化
,
transformation
,
deformation
,
grain ultrafinement
,
low carbon steels
祝东
,
蔡其巩
金属学报
本文研究了12Ni3CrMoVA合金钢流变应力随温度及应变速率的变化规律,以及组织因素的影响,测算了该材料激活能及激活体积等热激活参数。根据P-N机制由螺型位错芯结构分析了bcc金属的塑性形变规津,该规律同试验结果吻合,说明有效应力与温度关系曲线中的拐点是由于Peierls势能呈双驼峰分布所致,相应的位错线激活态形状呈双扭折对分布。显微组织仅影响位错的长程障碍阻力,而对位错热激活运动没有影响。
关键词:
热激活
,
deformation
,
strain rate
,
dislocation
刘建潮
,
郭蕴宜
,
邢中枢
,
师昌绪
金属学报
用金相显微镜、X射线衍射仪、透射电镜、磁强计等技术结合拉伸试验,研究了气相充氢与拉伸形变对三种奥氏体稳定性不同的Fe-Cr-Ni-Mn-N不锈钢马氏体转变和力学性能的影响,取得了一些定量的数据.结果表明,拉伸形变促进ε和α’马氏体在奥氏体不稳定的钢中的生成,而氢的存在能促进ε马氏体转变但抑制α’的产生.奥氏体不稳定的Fe-Cr-Ni-Mn-N钢比奥氏体稳定的同类钢抗氢脆能力差得多,这与ε马氏体的出现有关.
关键词:
Fe-Cr-Ni-Mn-N钢
,
austenitic steel
,
deformation
,
martensite
,
hydrogen embrittlement
尧志刚朱晓飞张广平
材料研究学报
采用显微压痕方法研究了Si、Ge、GaAs和InP四种半导体单晶的变形与断裂行为.通过测量[100]取向单晶体面内的显微硬度、裂纹开裂的临界压痕尺寸以及断裂韧性, 分析了这四种材料力学性能的面内各向异性行为. 结果表明: 在压痕载荷的作用下, Si和Ge的塑性变形以剪切断层为主, 而GaAs和InP则通过滑移系的开动协调变形. [100]取向的Si、Ge、GaAs和InP四种单晶的面内显微硬度、弹性模量和断裂韧性表现出不同程度的各向异性. 裂纹长度与压痕尺寸间的关系表明, 与GaAs和InP相比, Si、Ge具有较小的临界压痕尺寸和拟合直线斜率, 这一临界压痕尺寸和拟合直线斜率的变化规律分别与材料的硬度和断裂韧性的变化规律一致.
关键词:
无机非金属材料
,
semiconductor
,
microhardness
,
deformation
,
fracture toughness
,
anisotropy
何向明
,
戎利建
,
闫德胜
,
姜志民
,
李依依
金属学报
采用差示扫描量热仪(DSC)系统研究了在(Ms+30℃)温度下拉伸形变对Ti44Ni47Nb9$形状记忆合金应力诱发马氏体(SIM)相变行为的影响. DSC测量表明,SIM相变为一微观不均匀过程, 当形变量达到约14%时, SIM相变过程结束．在形变试样的第一次加热过程中, SIM的逆转变开始温度A's和相变潜热均随着形变量的增加先增加后略有降低; 而逆转变温度间隔随着形变量的增加略有增加,但和热诱发马氏体相比, SIM的逆转变温度间隔明显变窄．此宽滞后现象为一次性效应．在随后加热循环中的相变潜热、第一次冷却过程中马氏体相变开始温度以及第二次加热过程中逆转变开始温度均随着形变的增加而缓慢降低.
关键词:
Ti-Ni-Nb形状记忆合金
,
deformation
