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| 1 | Twin structure of the lath martensite in low carbon steel显示文摘It has been well accepted that the martensites in quenched carbon steels exhibit two typical morphologies which are closely dependent on the carbon content, i.e. lath martensite in low carbon steels and lenticular martensite in high carbon steels. Based on conventional belief, the lath martensites in low carbon steels are with high density dislocations as the substructure, in contrast to twin substructure in lenticular high carbon martensite. In the present work, an intensive transmission electron microscopy investigation was made to characterize the microstructures of the lath martensite in a low carbon steel of 0.2 wt%C. It was found that lots of lath martensites consist of twin as their substructure, rather than high density dislocations. In addition, nanoscale precipitates cohering with ferrite matrix were found at the twin interfaces. The orientation relationships between the precipitates and the ferrite matrix are in good agreement with that of primitive hexagonal ω phase in titanium alloys and other bcc metals or alloys. | Pan Zhang Yulin Chen Wenlong Xiao Dehai Ping Xinqing Zhao | 2016 | Progress in Natural Science:Materials International2016，26，2： | 6 |
| 2 | Review on ω Phase in Body-Centered Cubic Metals and Alloys显示文摘An to phase with a primitive hexagonal crystal structure has been found to be a common metastable phase in body-centered cubic(bcc) metals and alloys.In general,to phase precipitates out as a high density of nanoscale particles and can obviously strengthen the alloys;however,coarsening of the co particles significantly reduces the alloy ductility.The co phase has coherent interfacial structure with its bcc matrix phase,and its lattice parameters are a_ω =2^(1/2)×a_(bcc) and C_ω= 3^(1/2)/2 ×a_(bcc).The common {112}(11 l)-type twinning in bcc metals and alloys can be treated as the product of theω→ bcc phase transition,also known as the ω-lattice mechanism.The ω phase's behavior in metastable β-type Ti alloys will be briefly reviewed first since the ω phase was first found in the alloy system,and then the existence of the ω phase in carbon steels will be discussed.Carbon plays a crucial role in promoting the ω formation in steel,and the ω phase can form a solid solution with various carbon contents.Hence,the martensitic substructure can be treated as an α-Fe matrix embedded with a high density of nanoscale ω-Fe particles enriched with carbon.The recognition of the ω phase in steel is expected to advance the understanding of the relationship between the microstructure and mechanical properties in bcc steels,as well as the behavior of martensitic transformations,twinning formation,and martensitic substructure. | Dehai Ping | 2014 | Acta Metallurgica Sinica(English Letters)2014，27，1： | 4 |
| 3 | Determination of grain size by XRD profile analysis and TEM counting in nano-structured Cu 显示文摘 | Zhong Yong Ping Dehai Song Xiaoyan | 2009 | Journal of Alloys and Compounds2009，476，： | 1 |
| 4 | Microstructure of ultrahigh carbon martensite显示文摘Recent experimental investigations suggest that the martensite formed by quenching carbon steels(0.2–1.26 mass %C) are composed of twins and nanoscale ω particles in twin boundaries, rather than carbon supersaturated uniform solutions. In order to probe the microstructure of the martensite with ultrahigh carbon content, a novel strategy is employed in the present study to obtain ultrahigh carbon martensite(approximate2.1 mass %C) by quenching ductile cast iron. The microstructure of the martensite was intensively characterized by high resolution transmitting electron microscopy. It is indicated that the microstructure of the ultrahigh carbon martensites is composed of ultrafine {112} < 111 >-type twins and high-density nano-scaled ω particles embedded in twin boundaries. These ω nanoparticles in twin boundaries could remarkably impede the deformation of the movement of the nanotwins in martensites, leading to poor ductility and strength of the quenched ductile cast iron. These findings not only reveal the substructures of ultrahigh carbon martensite, but also enhance the understanding of the mechanical behavior of high carbon steels and ductile cast irons. | Chao Wang Yulin Chen Jingyun Han Dehai Ping Xinqing Zhao | 2018 | Progress in Natural Science:Materials International2018，28，6： | 0 |
| 5 | Microstructure Investigation on the Triple Junction with an Adjoining Twin Boundary in Nanocrystalline Palladium显示文摘By using high-resolution transmission electron microscopy,a [110] triple junction (TJ) containing a twin boundary (TB) in nanocrystalline palladium has been observed along the common axis direction.Molecular statics calculation and imaging simulation were performed to determine the atomic structure of the TJ.The modeling structure exhibits that the adjoining TB is a distorted one,whilst other two adjoining grain boundaries (GBs) exist in steady equilibrium states.The present observation gives a clear example demonstrating that the adjoining TB can release the larger stresses residing at the junction. | Yuchen Wang,Zhenxing Su and Dehai Ping Shenyang National Laboratory for Materials Science,Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China | 2010 | Journal of Materials Science & Technology2010，26，11： | 0 |
| 6 | FINE STRUCTURES OF BOTH INTERFACES AND INTERFACIAL REACTION PRODUCTS显示文摘The characteristic of interface depending on the atomic structure exerts an inportant,andsometime controlling,influence on performance of the interacial materials.The present paper reviews the main studies on fine structure of both the materials inter-faces and interfacial reaction products in semiconductor uperlattice,metal multilayer ceram-ics and composite materials by mean of selected area electron doffraction patterns and highresolution electron microscopy.The following features of interfaces are reviewed:the orientation relationships;the char-acteristic of steps,facets and ronghness of interfaces;atomic bonding across the interface;thedegree of coherency,the structure of misfit dislocations and elastic relaxations at the inter-faces:the presence of defects at the onterfaces:the structure of the interfacial reaction prod-ucts as well as the reaction kinetics and reaetion mechanism. | LI Douxing PING Dehai NING Xiaoguang YE Hengqiang Laboratory of Atomic Imaging of Solids,Institute of Metal Research,Academia Sinica,Shenyang.China Professor,Institute of Metal Research,Academia Sinica,Shenyang 110015,China | 1993 | Acta Metallurgica Sinica(English Letters)1993，6，1： | 0 |
| 7 | {332}<113> Twinning transfer behavior and its effect on the twin shape in a beta-type Ti-23.1Nb-2.0Zr-1.0O alloy显示文摘The interaction between twins and grain boundaries(GB) has an important influence on the deformation and fracture behavior of materials. In the present work, {332}<113> twinning transfer(TT) behavior and its effect on the twin shape in a deformed β-type Ti-23.1 Nb-2.0 Zr-1.0 O Ti alloy were investigated experimentally and with molecular dynamics simulation. The crystallographic alignment factor of the two twinning systems in the neighboring grains and the misorientation angle of the grain pairs were found to influence the occurrence of TT. This further determines the twin shape: twins present a ruler shape when TT occurs but are in a lenticular shape otherwise. Such different twin shapes are attributed to the local stress states related to TT occurring or not. Both ruler-shaped paired twinning and lenticular twinning would provide effective mechanisms to release or reduce the stress concentration in front of the twin tips in different grain pairs. | Yi Yang Bohua Zhang Zhichao Meng Lei Qu Hao Wang Sheng Cao Jianan Hu Hao Chen Songquan Wu Dehai Ping Geping Li Lai-Chang Zhang Rui Yang Aijun Huang | 2021 | Journal of Materials Science & Technology2021，，32： | 0 |
| 8 | Formation of Face‑Centered Cubic Phase in Ti35 Alloy Under In Situ Heating Transmission Electron Microscopy显示文摘A thermally induced hexagonal close-packed(HCP)to face-centered cubic(FCC)phase transition was investigated in anα-type Ti35 alloy with twinned structure by in situ heating transmission electron microscopy(TEM)and ab initio calculations.TEM observations indicated that the HCP to FCC phase transition occurred both within matrix/twin and at the twin boundaries in the thinner region of the TEM film,and the FCC-Ti precipitated as plates within the matrix/twin,while as equiaxed cells at twin boundaries.The crystallographic orientation relationship between HCP-Ti and FCC-Ti can be described as:{111}FCC//{0002}HCP and<110>FCC//<1210>HCP.The HCP to FCC phase transition was accomplished by forming an intermediate state with a BB stacking sequence through the slip of partial dislocations.The formation of such FCC-Ti may be related to the thermal stress and temperature.Ab initio calculations showed that the formation of FCC-Ti may also be related to the contamination of interstitial atoms such as oxygen. | Jianan Hu Mengmeng Yang Wenlong Xiao Hao Wang Dehai Ping Chengze Liu Shewei Xin Songquan Wu Kai Zhang Yi Yang Lai‑Chang Zhang Aijun Huang | 2023 | Acta Metallurgica Sinica(English Letters)2023，36，3： | 0 |
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