The Effects of Grain Size and Lubrication on Micro Curl Forming Process of Metallic Thin Sheet

2015 ◽  
Vol 661 ◽  
pp. 55-61
Author(s):  
Chang Cheng Chen ◽  
Huey Lin Ho
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Size Effect ◽  
Deformation Behavior ◽  
Thin Sheet ◽  
Grain Size Effect ◽  
Forming Process ◽  
Grain Sizes ◽  
Different Temperatures ◽  
Different Thickness

This article aims at the discussion of deformation behavior considering size effect on curl forming process of sheet metal. In this study, the test specimens were made by phosphor bronze sheets for curl forming test. The specimens with different thickness were firstly heated at different temperatures for obtaining the objective grain sizes. And the mechanical properties of specimen were acquired by using tensile test. Through the curl forming test with a curl forming machine, the curled angles, springback and curling load were measured and analyzed for investigating the grain size effect of the chamfer and carbon lubricant during the curl forming process.

Grain Size Effect on the Type VT1-0 Alloy Modified by Aluminum Ion Implantation

2015 ◽  
Vol 670 ◽  
pp. 144-151
Author(s):  
Irina Kurzina ◽  
Alisa Nikonenko ◽  
Natalja Popova ◽  
Elena L. Nikonenko ◽  
Mark Kalashnikov
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Ion Implantation ◽  
Size Effect ◽  
Phase State ◽  
Grain Size Effect ◽  
Significant Modification ◽  
Aluminum Ion ◽  
Grain Sizes ◽  
Aluminum Ions

The paper presents results of investigations of α-Ti microhardness modified by aluminum ions having diverse grain sizes, namely: 0.3 μm, 1.5 μm, and 17 μm. These investigations show that the decrease of the grain size and the additional ion implantation result in the significant modification of the structural and phase state of the alloy and its mechanical properties.

Grain Size Effect on Mechanical Behavior of Nanocrystalline Alloy Films

2017 ◽  
Vol 48 ◽  
pp. 204-210
Author(s):  
Bing Yang Ma ◽  
Kai Cheng Shi ◽  
Hai Long Shang ◽  
Jin Yan Qi ◽  
Rong Bn Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Nanocrystalline Alloy ◽  
Nanocrystalline Alloys ◽  
Grain Size Effect ◽  
Mechanical Behaviors ◽  
Multilayered Films ◽  
Grain Sizes ◽  
Pure Metals ◽  
Different Thickness

The effect of grain size in nanocrystalline alloys is difficult to analyze because challenges of controlling a number of other microstructure factors. This paper designed and prepared a series of multilayered films with Al-Zr crystalline layers of different thickness but with amorphous layers of identical thickness. In these multilayered films, the heights of columnar crystals in crystalline layers were controlled from 5 to 160 nm and their diameters were kept at 10 to 15 nm, independent of their heights. This design achieved the control of grain size, independent from other microstructure factors. The analysis of mechanical properties of these multilayered films showed that the inverse Hall-Petch phenomenon also exists in Al-Zr nanocrystalline alloys. The critical grain sizes of deviation from the Hall-Petch relationship and the inverse Hall-Petch phenomenon are approximately 40 nm and 10 nm respectively. These mechanical behaviors of nanocrystalline alloys are similar to those reported in pure metals.

Grain Size Effect on Saddle Phenomenon in V-Bending Process of Thin Sheet Metal

2018 ◽  
Vol 773 ◽  
pp. 202-207
Author(s):  
Chang Cheng Chen ◽  
Yi Xiang Hong
Keyword(s):  
Grain Size ◽  
Size Effect ◽  
Sheet Metal ◽  
Design Method ◽  
Tensile Force ◽  
Thin Sheet ◽  
Grain Size Effect ◽  
Sheet Metal Parts ◽  
Grain Sizes ◽  
Thin Sheet Metal

The ability for predicting the springback on sheet metal bending processes is identified as an important feature of the ability for predicting the final geometry of sheet metal parts. The grain size effect makes the difficult on application of traditional design method in processing. As through tool and processing design, to understand the effects of grain size effects is an important and powerful way to effectively compensate for and eliminate the springback. In this paper, 99.5% pure iron specimens were annealed at different temperature to obtain the specified grain sizes. The effects of different grain sizes on the saddle after V-bending of the thin sheet metal were investigated. The results show that at the same thickness of specimens, the grain size has no significant effect on the saddle height. However, with increasing the thickness of the specimens the saddle will also be more prominent protruding height. The concave side of bent specimen is against the compression force and its grains structure tend to a round shape, whereas the convex side is against the tensile force and its grains structure tend to a flaky shape.

scholarly journals Size Effect on Mechanical Properties and Deformation Behavior of Pure Copper Wires Considering Free Surface Grains

Materials ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 4563
Author(s):  
Yu Hou ◽  
Xujun Mi ◽  
Haofeng Xie ◽  
Wenjing Zhang ◽  
Guojie Huang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Free Surface ◽  
Size Effect ◽  
Single Crystal ◽  
Deformation Behavior ◽  
Pure Copper ◽  
Critical Value ◽  
Wire Diameter ◽  
Surface Model

The size (grain size and specimen size) effect makes traditional macroscopic forming technology unsuitable for a microscopic forming process. In order to investigate the size effect on mechanical properties and deformation behavior, pure copper wires (diameters range from 50 μm to 500 μm) were annealed at different temperatures to obtain different grain sizes. The results show that a decrease in wire diameter leads to a reduction in tensile strength, and this change is pronounced for large grains. The elongation of the material is in linear correlation to size factor D/d (diameter/grain size), i.e., at the same wire diameter, more grains in the section bring better plasticity. This phenomenon is in relationship with the ratio of free surface grains. A surface model combined with the theory of single crystal and polycrystal is established, based on the relationship between specimen/grain size and tensile property. The simulated results show that the flow stress in micro-scale is in the middle of the single crystal model (lower critical value) and the polycrystalline model (upper critical value). Moreover, the simulation results of the hybrid model calculations presented in this paper are in good agreement with the experimental results.

Heterogeneity Effects in X-Ray Analysis*

1961 ◽  
Vol 5 ◽  
pp. 335-354 ◽  
Author(s):  
Fernand Claisse ◽  
Claude Samson
Keyword(s):  
Grain Size ◽  
Size Effect ◽  
Mathematical Treatment ◽  
Grain Size Effect ◽  
Light Elements ◽  
X Ray Diffraction ◽  
Limited Region ◽  
X Ray ◽  
Grain Sizes ◽  
Heterogeneity Effects

AbstractA fundamental quantitative treatment of the heterogeneity effects in X-ray fluorescence has been made. The theory predicts that the grain-size effect appears only in a limited region of grain sizes which depends on the wavelength of the primary radiation and the nature of the compounds in the mixture. With monochromatic radiation, the fluorescence intensity showed increase or decrease by a factor of a few units as grain size is decreased, A factor as large as 12, the theoretical value, has been observed in one particular experiment. Usually the grain-size effect can be eliminated by intensive grinding. For the light elements fine grinding is disastrous if long wavelengths are used. By an appropriate choice of the wavelength it is possible to eliminate the effect even without grinding. The mathematical treatment also predicts, but less rigorously, a grain-size effect in X-ray diffraction.The effect on the fluorescence intensities by changes in the chemical composition of the grains that contain the fluorescent element is predicted by the theory.These findings are discussed in relation to the analysis of elements when polychromatic beams are used.

Progressive and Compound Forming for Producing Plunger-Typed Microparts by Using Sheet Metal

2020 ◽  
Vol 8 (2) ◽  
Author(s):  
Jun-Yuan Zheng ◽  
Ming-Wang Fu
Keyword(s):  
Grain Size ◽  
Size Effect ◽  
Sheet Metal ◽  
Mass Production ◽  
Grain Size Effect ◽  
Sheet Metals ◽  
Forming Process ◽  
Deformation Behaviors ◽  
Progressive Forming ◽  
Insight Into

Abstract The plunger part in temporary electronic connectors is traditionally fabricated by micromachining. Progressive forming of microparts by directly using sheet metals is developed and proven to be an efficient microforming process to overcome some intrinsic drawback in realization of mass production of microparts. By employing this unique micromanufacturing process, an efficient approach with progressive microforming is developed to fabricate plunger-shaped microparts. In this endeavor, a progressive forming system for making microplungers using extrusion and blanking operations is developed, and the grain size effect affected deformation behaviors and of surface qualities of the microformed parts are studied. The knowledge for fabrication of plunger-shaped microparts via progressive microforming is developed, and the in-depth understanding and insight into the deformation behaviors and tailoring the product quality and properties will facilitate the design and development of the forming process by using this unique microforming approach.

Grain size effect of pre- and post-coating treated cemented carbides on PVD films' adhesion and mechanical properties

2013 ◽  
Vol 44 (8) ◽  
pp. 697-703 ◽  
Author(s):  
K.-D. Bouzakis ◽  
N. Michailidis ◽  
G. Skordaris ◽  
A. Tsouknidas ◽  
S. Makrimallakis ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Size Effect ◽  
Cemented Carbides ◽  
Grain Size Effect

scholarly journals Grain Size Effect on the Mechanical Behavior of Cohesionless Coarse-Grained Soils with the Discrete Element Method

2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Renjie Wen ◽  
Cai Tan ◽  
Yong Wu ◽  
Chen Wang
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Shear Strength ◽  
Size Effect ◽  
Discrete Element Method ◽  
Discrete Element ◽  
Force Chain ◽  
Coarse Grained ◽  
Biaxial Compression ◽  
Grain Sizes

Biaxial compression tests with the same specimen size and different maximum grain sizes were simulated for coarse-grained soils using the discrete element method to study the influence of grain size on the mechanical properties and force chain. The maximum grain sizes were 40, 20, 10, and 5 mm, respectively. The grading with self-similar fractal structure in mass is designed to ensure the same pore structure for soils. The shear strength increased with the increase in maximum grain size. Evident increase in shear strength and significant size effect were observed when the ratio of the specimen diameter to maximum grain size was less than five. The shear dilation of coarse-grained soils increases with the increase in maximum grain size. The contact force distribution was uniform when maximum grain size was small but tends to be uneven with the increase in maximum grain size, thereby causing the increase in shear strength by stable strong force chains. This finding demonstrates size effect on the mechanical properties and force chain of cohesionless coarse-grained soils under the biaxial compression condition.

GRAIN SIZE EFFECT ON THE COLOSSAL MAGNETORESISTANCE IN GRANULAR PEROVSKITE La0.7Pb0.3MnO3

2006 ◽  
Vol 20 (29) ◽  
pp. 1859-1865 ◽  
Author(s):  
S. L. YOUNG ◽  
H. Z. CHEN ◽  
M. C. KAO ◽  
L. HORNG ◽  
K. M. WU ◽  
...  
Keyword(s):  
Grain Size ◽  
Magnetic Susceptibility ◽  
Size Effect ◽  
Colossal Magnetoresistance ◽  
Double Exchange ◽  
Tunneling Effect ◽  
Grain Size Effect ◽  
Double Exchange Interaction ◽  
Grain Sizes ◽  
Ferromagnetic Ordering

Magnetic behaviors and transport properties in granular perovskite La 0.7 Pb 0.3 MnO 3 with different grain sizes have been synthesized. The results show that magnetic susceptibility, ferromagnetic ordering temperature and magnetoresistance are affected by the grain size. These compounds with different grain sizes exhibit two kinds of magnetoresistance origins, intragrain double exchange and intergrain interfacial tunneling. With the increasing grain size, the intrinsic transport is dominant while the extrinsic tunneling gradually disappears. Thus, the basis of magnetotransport mechanism is the result of competition between the double exchange interaction and the interfacial tunneling effect.

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