Variant organization and mechanical detwinning of modulated martensite in Ni-Mn-In metamagnetic shape-memory alloys
Variant organization and mechanical detwinning of modulated martensite in Ni-Mn-In metamagnetic shape-memory alloys
复制标题
Ni-Mn-In变磁形状记忆合金中调制马氏体的变体组织和机械解孪
DOI：
10.1016/j.actamat.2016.03.049
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发表时间：
2016
期刊：
影响因子：
9.4
通讯作者：
Zuo Liang
中科院分区：
文献类型：
--
作者：
Yan Haile;Yang Bo;Zhang Yudong;Li Zongbin;Esling Claude;Zhao Xiang;Zuo Liang
根据显微组织和结晶学特征，研究了Ni-Mn-In合金中6M调制马氏体的变形组织和机械脱孪晶。在无应力环境下，每个马氏体团由四个不同的取向变体组成，它们在三个孪生关系中相互关联。具有I型孪生关系的相邻变体具有直界面，而具有II型或复合孪生关系的相邻变体具有原子尺度上的阶梯界面。施密德因子(SF)计算表明，在单轴压缩条件下，I型和II型脱孪系的高Sf值加载取向区彼此接近，与复合脱孪系的取向区相差约90°。不同类型孪晶的去孪生阻力被认为与孪生剪切力和孪晶边界组织有关。虽然具有相同的孪生剪切量(0.2392)，但I型孪晶具有比II型孪晶大得多的去孪晶阻力。复合孪晶具有最小的去孪晶阻力，这得益于其细小的孪生剪切量(0.0277)和阶梯状孪晶界面。在外加载下，如果加载方向有利，马氏体变异体在团体内通过脱孪晶发生局部反应。当加载方向位于三个去孪晶系统的共同正SF区时，在某些群体中有可能获得单一的变异态。本研究可望为6MNi-Mn-In马氏体形变过程中的局部变形重取向提供基础信息。
Based upon microstructural and crystallographic characterizations, the variant organization and mechanical detwinning of 6M modulated martensite in Ni–Mn–In alloys have been studied. In the stress-free circumstance, each martensite colony is composed of four distinct orientation variants that are related to one another in three twin relations. Adjacent variants with type-I twin relation possess straight interfaces, whereas those with type-II or compound twin relation have stepped interfaces at atomic scale. Schmid factor (SF) calculations show that under uniaxial compression condition, the loading orientation zones with high SFs for the type-I and type-II detwinning systems are close to each other, being at about 90° away from those of the compound detwinning system. The detwinning resistances of the different types of twins are considered to be associated with their twinning shears and twin boundary structures. Type-I twin possesses much larger detwinning resistance than that of type-II twin, though they have the same amount of twinning shear (0.2392). Compound twin has the smallest detwinning resistance, which is benefited from its tiny twinning shear (0.0277) and stepped twin interface. Under external loading, martensite variants react locally within colonies through detwinning if the loading orientation is favorable. It is possible to obtain single variant state in some colonies when the loading orientation is located in the common positive SF zone of the three detwinning systems. This study is expected to provide fundamental information on local variant reorientation of 6M Ni–Mn–In martensite during deformation.