scholarly journals Microstructure Characterization and Mechanical Property of Mg/Al Laminated Composite Prepared by the Novel Approach: Corrugated + Flat Rolling (CFR)

Metals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 690 ◽  
Author(s):  
Tao Wang ◽  
Sha Li ◽  
Zhongkai Ren ◽  
Yi Jia ◽  
Wenshi Fu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Rolling Direction ◽  
Laminated Composite ◽  
Rolling Process ◽  
Interfacial Microstructure ◽  
Rolled Sample ◽  
Novel Approach ◽  
Flat Rolling ◽  
Interfacial Intermetallic Compounds

In this paper, Mg/Al laminated composites were successfully prepared at 400 °C by corrugated + flat rolling (CFR) with reduction ratios of 35% and 25% and subsequent annealing treatments were conducted at 200–350 °C for 30 min. A two-dimensional model was established to analyze the strain distribution during the first corrugated rolling process. Simulation results indicated that severe plastic deformation was formed at trough positions, which included more numerous refined grains than in the peak positions. The interfacial microstructure and mechanical property of the flattened composites along the rolling direction (RD) and the transverse direction (TD) were investigated. The results revealed that longitudinal discontinuous and transverse continuous interfacial intermetallic compounds (IMCs) were observed of the flattened as-rolled sample. Spatial distribution was provided for the grain microstructure along the thickness and rolling direction for AZ31B magnesium alloys of the CFR as-rolled composite. Mechanical property results showed that the longitudinal ultimate tensile strength (UTS) and elongation (EL) of the as-rolled sample reached 255 MPa and 4.14%, respectively. The as-rolled UTS along TD reached 325 MPa, about 30% higher than that along the RD. After heat treatment, the anisotropy of mechanical properties remained. The microstructure evolution and mechanical properties were discussed in detail.

scholarly journals Mechanical and electrical properties of polylactic acid/carbon nanotube composites by rolling process

2018 ◽  
Vol 25 (5) ◽  
pp. 891-901 ◽  
Author(s):  
Lijun Wang ◽  
Jianhui Qiu ◽  
Eiichi Sakai
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotube ◽  
Electrical Properties ◽  
Polylactic Acid ◽  
Molecular Orientation ◽  
Rolling Direction ◽  
Rolling Process ◽  
Molecular Structures ◽  
Scanning Calorimetry ◽  
Mechanical And Electrical Properties

AbstractIn this work, the rolling process was employed to fabricate polylactic acid/multi-walled carbon nanotube (PLA/MWCNT) composites at room temperature. The effects of the rolling conditions on the mechanical and electrical properties of the fabricated composites were investigated. The evolution processes of the internal molecular structures, i.e. changes in molecular orientation and crystallinity, were examined by X-ray diffraction, differential scanning calorimetry, and density method. The results suggested that the molecular orientation improved; however, the crystallinity decreased when the rolling ratio increased. The analysis of the mechanical properties revealed that the rolled composites displayed anisotropy during the rolling process. In the rolling direction, after adding 1 wt.% MWCNTs, the tensile strength increased from 58.6 to 94.3 MPa with the rolling ratio, whereas the fracture strain sharply increased to 131.5% at the rolling ratio of 60%. In addition to the mechanical properties, electrical resistivity was also investigated; notably, this property was not significantly affected by the rolling process. Furthermore, the MWCNT dispersion and morphology were investigated by scanning electron microscopy. These findings offer a simple and effective method to fabricate conductive composites with excellent mechanical properties.

Influences of Tensile Temperature on the Mechanical Properties of Rolled Mg-Zn-Gd Sheets with Non-Basal Texture

2015 ◽  
Vol 816 ◽  
pp. 381-386
Author(s):  
H. Yan ◽  
R.S. Chen ◽  
E.H. Han
Keyword(s):  
Mechanical Properties ◽  
Room Temperature ◽  
Tensile Deformation ◽  
Rolling Direction ◽  
Tensile Tests ◽  
Rolling Process ◽  
Basal Texture ◽  
Forming Process ◽  
Microstructure Observation ◽  
Increasing Temperature

Mg-2.0Zn-xGd sheets with non-basal texture were fabricated by common rolling process, which showed excellent ductility and formability at room temperature. In this paper, tensile tests were carried out at moderate temperature along the rolling direction and transverse direction to evaluate the influences of tensile temperature on mechanical properties and formability of the sheet. The microstructural evolution during tensile deformation was also investigated to analysis deformation mechanisms. The results showed that the elongation of the sheets increased from 57% at 373K to 253% at 573°C along the rolling direction, while the yield strength decreased with the increase of tensile temperature. The microstructure observation indicated that twining was one of the deformation modes and no dynamic recrytallization took place during deformation at 373K. With temperature increasing up to 473K, dynamic recrystallization took place and led to finer microstructure. This suggests that the formability of the Mg-Zn-Gd sheets with high ductility at room temperature could be further improved by increasing temperature up to 473K, which could refine the microstructure leading to higher strength during second forming process.

scholarly journals Microstructure and Mechanical Properties of Mg/Al Clad Bars with Ni Interlayer Processed by Compound Castings and Multi-Pass Caliber Rolling

Metals ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 704 ◽  
Author(s):  
Lu Chen ◽  
Ying Fu ◽  
Fuxing Yin ◽  
Ning Liu ◽  
Chunyong Liang
Keyword(s):  
Mechanical Properties ◽  
Rolling Force ◽  
Core Layer ◽  
Casting Process ◽  
Rolling Process ◽  
Interfacial Microstructure ◽  
Inhomogeneous Strain ◽  
Microstructure And Mechanical Properties ◽  
Compound Casting ◽  
Ni Interlayer

Magnesium/aluminium clad bars were fabricated by compound casting and multi-pass warm caliber rolling. A Ni interlayer prepared using a plasma spraying process was inserted between the parent metals to improve the interfacial characteristics during the casting process, and the effect of caliber rolling on the evolution of the interfacial microstructure and mechanical properties of the Mg/Ni/Al composites was investigated. The results show that the formation of Mg-Al intermetallic phases was impeded effectively by the Ni interlayer and a typical AZ31/Ni/6061 multilayer structure with metallurgical bonding was formed during the compound casting process. In addition, an inhomogeneous strain distribution in the AZ31 and 6061 alloys were characterized during the rolling process. The AZ31 clad layer accommodated a larger proportion of the plastic strain during the initial passes, while the strain in the Mg core layer increased with increasing number of passes. The Ni interlayer fragmented during the rolling process, and transformed into the dispersed particles at the interface. Meanwhile, the fresh AZ31 and 6061 base alloys squeezed out and bonded together under the rolling force, and a well-bonded interface with no visible defects was formed.

Microstructure and Texture Dependence of Asymmetric Rolled AZ31 Mg Alloy

2007 ◽  
Vol 345-346 ◽  
pp. 77-80
Author(s):  
Jae Seol Lee ◽  
Hyeon Taek Son ◽  
Young Kyun Kim ◽  
Ki Yong Lee ◽  
Hyoung Mo Kim ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Transverse Direction ◽  
Rolling Direction ◽  
Rolling Process ◽  
Fiber Texture ◽  
The Other ◽  
Asymmetric Rolling ◽  
Rolled Sample ◽  
Deformation Twins ◽  
Az31 Mg Alloy

In this study, we try to investigate the asymmetric rolling process affects microstructure, texture and formability of AZ31 Mg sheet. The deformation twins are clearly apparent, small and recrystallized grains are visible along some grain boundary and twinned regions in the as-rolled both samples. The symmetrically rolled sample tended to show peak inclined to the rolling direction. On the other hand, the asymmetrically rolled sample tended to show peak slightly inclined to the transverse direction. From the pole figure observation by EBSD, the intensity decrease of basal fiber texture after asymmetric rolling should be attributed to the severe shear strain induced during asymmetric process. The Erichsen value was measured to be 6.5 for asymmetrically rolled sample and 5.2 for symmetrically rolled sample.

Deformation Behavior of Hollow Axles With Constant Hole Diameter by Three-Roll Skew Rolling

2020 ◽  
Author(s):  
Song Zhang ◽  
Xuedao Shu ◽  
Jitai Wang ◽  
Chang Xu
Keyword(s):  
Mechanical Properties ◽  
Rolling Direction ◽  
Rolling Process ◽  
Hole Diameter ◽  
Stress And Strain ◽  
Forming Process ◽  
Processing Efficiency ◽  
Forming Quality ◽  
Material Utilization ◽  
Skew Rolling

Abstract At present, hollow axles with constant hole diameter is mainly formed by turning thick-walled hollow tubes. This method of processing has low material utilization and processing efficiency. And heat treatment is required to improve the mechanical properties of hollow axles. To improve the material utilization and processing efficiency of hollow axles with constant hole diameter during the forming process, a new processing technique, three-roll skew rolling process, is proposed to form a hollow axles with constant hole diameter in this paper. The three-roll skew rolling process is a continuous plastic forming process, which has high material utilization and processing efficiency, and it can improve the mechanical properties of the rolled parts. Firstly, combining the working principle of three-roll skew rolling and the structural characteristics of hollow axles with constant hole diameter, the forming mechanism of hollow axles with constant hole diameter by three-roll skew rolling is described. Secondly, the finite element model of the hollow axles with constant hole diameter by three-roll skew rolling is established according to the dimensions of the hollow axles with constant hole diameter, the material characteristics of the hollow axles, and the stable rolling conditions of three-roll skew rolling. The process parameters of the hollow axles are also determined. Thirdly, according to each step position of the hollow axles, the forming process of the hollow axles with constant hole diameter by three-roll skew rolling is divided into 5 deformation stages. Lastly, the stress and strain field of each deformation stage of the hollow axles was analyzed. The results show that the dimensions of the hollow axles with constant hole diameter by three-roll skew rolling are very close to the designed dimensions, which indicates that the material utilization of the rolled hollow axles is very high. Along the rolling direction, the descending step of the hollow axle is easier to form than the ascending step, and the forming quality is also better. The surface metal of the rolled hollow axles flows faster than the internal metal. Areas with large stress and strain are mainly concentrated at both ends of the rolled hollow axles. And the magnitude of stress and strain gradually decrease from the surface to the center. The hollow axles with constant hole diameter by three-roll skew rolling has a good forming quality and high forming efficiency. The hollow axles with constant hole diameter is formed by three-roll skew rolling process, which has broad application prospects.

Microstructure and Mechanical Properties of Multi-Pass Warm Rolled Ti-6Al-4V Alloy of Different Microstructures

2016 ◽  
Vol 716 ◽  
pp. 871-876
Author(s):  
Yong Xu ◽  
Xiang Jie Yang ◽  
Dan Ni Du
Keyword(s):  
Mechanical Properties ◽  
Rolling Direction ◽  
Rolling Process ◽  
Warm Rolling ◽  
Strengthening Effect ◽  
Test Results ◽  
Microstructure And Mechanical Properties ◽  
Rolled Specimen ◽  
The Difference ◽  
Conventional Rolling

In this investigation three kinds of raw microstructure Ti-6Al-4V alloys were studied using two directional rolling on a conventional rolling mill. The effect of deformation on microstructure and mechanical properties has been attempted. Microstructural observation indicated that the size of the lamellar/equiaxed α grain was sharply decreased to submicro after multi-pass warm rolling. Tensile test results showed that the multi-pass warm rolling process was found to have a remarkable strengthening effect. The ultimate tensile strength and yield stress were increased by more than 10% and 25% respectively compared with unidirection rolled specimen, and the elongation has been increased by more than one times, and the maximum is up to 1.58 times. Meanwhile, the difference of the strength and elongation between in rolling direction and in transverse direction has been greatly reduced.

Microstructure Evolution of PtTi0.5Zr0.2/Ti Laminated Composites Synthesized by Hot Pressing and Rolling

2015 ◽  
Vol 815 ◽  
pp. 656-660
Author(s):  
Ye Fan ◽  
Xiao Ge Zhang ◽  
Qiong Zhao ◽  
Guo Yi Qin ◽  
Si Yong Xu ◽  
...  
Keyword(s):  
Mechanical Property ◽  
Tensile Strength ◽  
Intermetallic Compound ◽  
Microstructure Evolution ◽  
Hot Pressing ◽  
Laminated Composites ◽  
Laminated Composite ◽  
Rolling Process ◽  
Tensile Fracture ◽  
Layer Structures

The PtTi0.5Zr0.2/Ti laminated composite was prepared by hot pressing and rolling process. Microstructure, interlaminar spacing and mechanical property of the microlaminated composites after rolling were evaluated. The results showed that the layer structures of laminated composites remained consecutiveness with 93% deformation. The 12μm PtTi0.5Zr0.2 layer and 8μm Ti layer was observed finally, as well as the intermetallic compound Ti3Pt making the PtTi0.5Zr0.2 layer and Ti layer connect with each other. Compared with Platinum and Titanium, the tensile strength of PtTi0.5Zr0.2/Ti laminated composite was enhanced by approximately 59% and 29% respectively and reached 657MPa. The tensile fracture was more uniform and showed a more coordinated process.

A TEM study of the interface between organic matrix and aragonite in a biological hard tissue, nacre

1992 ◽  
Vol 50 (2) ◽  
pp. 1024-1025
Author(s):  
Jun Liu ◽  
Katie E. Gunnison ◽  
Mehmet Sarikaya ◽  
Ilhan A. Aksay
Keyword(s):  
Mechanical Properties ◽  
Ion Beam ◽  
Laminated Composite ◽  
Organic Matrix ◽  
Pearl Oyster ◽  
Interfacial Structure ◽  
Interfacial Region ◽  
Thin Sections ◽  
Organic Layers ◽  
Transmission Electron

The interfacial structure between the organic and inorganic phases in biological hard tissues plays an important role in controlling the growth and the mechanical properties of these materials. The objective of this work was to investigate these interfaces in nacre by transmission electron microscopy. The nacreous section of several different seashells -- abalone, pearl oyster, and nautilus -- were studied. Nacre is a laminated composite material consisting of CaCO3 platelets (constituting > 90 vol.% of the overall composite) separated by a thin organic matrix. Nacre is of interest to biomimetics because of its highly ordered structure and a good combination of mechanical properties. In this study, electron transparent thin sections were prepared by a low-temperature ion-beam milling procedure and by ultramicrotomy. To reveal structures in the organic layers as well as in the interfacial region, samples were further subjected to chemical fixation and labeling, or chemical etching. All experiments were performed with a Philips 430T TEM/STEM at 300 keV with a liquid Nitrogen sample holder.

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