孪晶界

单晶Ni-Mn-Ga孪晶界迁动机制研究及应力诱发马氏体相变模拟

Research on the Mechanism of the Twin Boundary Motion of Ni-Mn-Ga Single Crystals and the Simulation of Stress-induced Martensitic Transformation

此外，在Ni孪晶界附近存在较多生长缺陷&Frank位错。

Furthermore , there are quite many growth defects-Frank dislocations near the Ni twin boundary .

断裂面是｛111｝γ或孪晶界；

The fracture plane is the { 111 } _ γ or twin boundary .

高氮奥氏体钢中退火孪晶界及其断裂刻面的特征

Characteristics of Annealing Twin Boundary and its Fracture Facet in a High-nitrogen Bearing Austenitic Steel

结果显示两种挤压态镁合金室温变形都很不均匀，裂纹主要形核于孪晶界和聚集的粗大第二相上。

Results show that the plastic deformation of as-extruded Mg alloys tends to be rather heterogeneous .

孪晶界阻碍位错运动导致高的加工硬化率；

The twin boundaries act as strong obstacles to the dislocation motion , so lead to higher strain-hardening .

低温变形中会产生部分孔洞，孔洞大多分布在孪晶界和晶界处，对孪晶生长起阻碍作用。

Most of cavities which hinder the growth of twinning distribute on the grain boundaries and twinning boundaries .

螺位错在孪晶界上分解导致沿着孪晶界发生弯曲和凹痕甚至孪晶的断裂。

The kink or flaw along the twin boundary is resulted by the screw dislocations dissociation at the twin boundary .

受温度热涨落的影响，孪晶界迁移的临界剪切应力随温度的升高而降低。

With the aid of thermal fluctuations , the critical shear stress required for TB migration decreases with elevating temperature .

发现晶体中存在有孪晶界、位错、生长带和亚结构等多种缺陷。

The results showed that in the specimens there exist crystal defects such as twin boundary , dislocation , growth bands and substructure .

然而，孪晶界间距的改变对孪晶的屈服应力和强度的影响甚微。

The influence of the spacing between two twin planes , however , seems to be less significant for the yielding stress and strength .

孪晶界能够有效阻碍由孔洞发射的位错的运动，从而大幅度提高晶体的强度。

However , the strength of NT copper is significantly enhanced by these coherent TBs , which can efficiently impede the motion of dislocations emitted from nanoscale voids .

金属和合金中的面缺陷包括晶界、亚晶界、孪晶界、相界、堆垛层错、外表面等。

The plane defects of metals and alloys include grain boundary , sub-grain boundary , twins grain boundary , phase boundary , stacking fault , outward surface , etc.

能跨越原晶界或孪晶界而生长，并仍保留原奥氏体晶界的痕迹，但不继承孪晶组织。

It grows across the grain boundaries of parent phase or the twin , the trace of austenite boundary being preserved , but there is not any inheritance of twin structure .

第3个峰与{101}孪晶界的驰豫过程有关。

And the last one is due to a relaxation process associated with the movement of the { 101 } - twin boundaries in the fct phase or fcc antiferromagnetic phase .

对断面与侧面组织的双面观察表明，退火孪晶界断裂、沿晶断裂和穿晶断裂分别形成光滑平面状断裂刻面、光滑曲面状断裂刻面和粗糙不平的断裂刻面。

The dual-plane observations of fracture surface and adjacent side surface microstructures show that annealing twin boundary fracture , intergranular and transgranular cracking result in smooth planar facet , smoothly curved facet and rough facet , respectively .

分析表明该单晶的大自发相变应变量起源于内应力诱导的变体择优取向，而磁增强的相变应变量归功于外加磁场通过孪晶界移动的方式诱导的变体择优取向。

Investigation indicates that the large spontaneous strain originates from the preferential orientation of variants induced by the residual internal stress and the field-enhanced transformation strain is attributed to the preferential orientation of variants performed by twin boundary motion .

原位拉伸试验研究表明撞击诱发的微裂纹、微孔洞、绝热剪切带及孪晶界是主裂纹形核和扩展的主要路径，大量缺陷的形成降低了材料抵抗继续变形的能力。

The situ tensile tests show that the microcracks , microvoids , ASBs and twin boundary induced by high velocity impact were the preferential sites for the nucleation and propagation of the primary cracks , and the formation of various defects led to the further deformability of the materials decreasing .

PTC型BaTiO3陶瓷的孪晶和孪晶界

Twin and twin boundary in PTC batio_3 ceramics

γ-TiAl基合金块状组织中孪晶与反相畴界的相互作用

Interaction between the Twins and the Anti-Phase Boundaries in Massive Transformation for γ - TiAl Alloys

塑性应变幅大于8.14×10-4时，孪晶的约束作用、孪晶界与位错的反应及孪晶中位错的特殊组态，使多晶铜的循环饱和应力提高，硬化曲线中应力饱和平台区延长。

When plastic strain amplitude was higher than about 8.14 × 10-4 , twins will elevate fatigue saturation stress and extend stress saturation plateau because of the interactions between twin boundaries and dislocations .

低温峰在淬火温度为700℃时有一最小值之后随淬火温度的升高而升高，因为在较高温度淬火可产生较大尺寸的孪晶，从而有利于孪晶畴界的移动。

The low-temperature peak rose with increasing quench temperature because relatively high quench temperature produced relatively coarse twins whith were favorable for the sliding motion of the twins .

磁致伸缩型微位移致动器通常采用多晶或孪晶结构材料作为驱动单元，由于晶界和孪晶界对畴壁的移动具有阻碍作用，其低场下的位移输出较小，调控精度受到较大影响。

Tb-Dy-Fe twin crystal or polycrystal magnetostrictive materials are normally employed as driving unit in magnetostrictive actuator , yet the crystal boundary and twin crystal structure in the Tb-Dy-Fe materials hinder the movement of domain walls so that the displacement output under low magnetic field is rather small .