scholarly journals Comparison of the Structural Evolution of β Polypropylene During the Sequential and Simultaneous Biaxial Stretching Process

2020 ◽  
Author(s):  
Daoxin Zhang ◽  
Lei Ding ◽  
Feng Yang ◽  
Fang Lan ◽  
Ya Cao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Structural Evolution ◽  
Deformation Mode ◽  
Microporous Membranes ◽  
Biaxial Stretching ◽  
Coarse Fibers ◽  
Deformation Modes ◽  
Stretching Process

In this paper, the lamellar structural evolution and microvoids variations of β-iPP during the processing of two different stretching methods, sequential biaxial stretching and simultaneous biaxial stretching, were investigated in detail. It was found that different stretching methods led to significantly different lamellae deformation modes, and the microporous membranes obtained from the simultaneous biaxial stretching exhibited better mechanical properties. For the sequential biaxial stretching, abundant coarse fibers originated from the tight accumulation of the lamellae parallel to the longitudinal stretching direction, whereas the lamellae perpendicular to the stretching direction were easily deformed and separated. Those coarse fibers were difficult to be separated to form micropores during the subsequent transverse stretching process, resulting in a poor micropores distribution. However, for the simultaneous biaxial stretching, the β crystal had the same deformation mode, that is, the lamellae distributed in different directions were all destroyed, forming abundant microvoids and little coarse fibers formation.

Mechanical Properties of Fine-Grained AA1050 after ECAP

2006 ◽  
Vol 503-504 ◽  
pp. 847-852 ◽  
Author(s):  
Stijn Poortmans ◽  
Bert Verlinden
Keyword(s):  
Mechanical Properties ◽  
Strain Hardening ◽  
Room Temperature ◽  
Deformation Mode ◽  
Fine Grained ◽  
Tension Tests ◽  
Hot Rolled ◽  
Deformation Tests ◽  
Deformation Modes ◽  
Cylindrical Samples

The mechanical properties of fine-grained Aluminium AA1050 produced by ECAP at room temperature, have been investigated under various deformation modes. Because ECAP leads to an unstable microstructure, some samples were annealed at 300°C for 10 minutes in order to stabilise the microstructure. For mechanical testing, cylindrical samples were used in three types of monotonic deformation tests: axisymmetric compression, uniaxial tension and simple shear by torsion. The influence of the deformation mode on the yield locus and strain hardening behaviour has been studied and will be discussed for both hot rolled AA1050, ECAP samples without annealing and annealed ECAP samples. To achieve a better understanding of the strain hardening, some preliminary tests with a change in strain path were also performed. The results of tension tests followed by compression will be reported.

A new type of bionic grid plate—The compressive deformation and mechanical properties of the grid beetle elytron plate

2021 ◽  
pp. 109963622199387 ◽  
Author(s):  
Ning Hao ◽  
Jinxiang Chen ◽  
Yiheng Song ◽  
Xiaoming Zhang ◽  
Tidong Zhao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Deformation Mode ◽  
Absorption Capacity ◽  
Compressive Deformation ◽  
Compressive Properties ◽  
New Type ◽  
Grid Plate ◽  
Three Stages ◽  
First Time ◽  
Deformation Modes

To develop lightweight and biomimetic structural materials, in this paper, the compressive deformation and mechanical properties of the grid beetle elytron plate (GBEP) with the same core volume as the end-trabecular beetle elytron plate (EBEP) under compression were investigated for the first time. (1) The B-type deformation mode of trabeculae is clarified, which is a higher stage of independent deformation than the Φ-type deformation mode in the beetle elytron plate (BEP). Additionally, the four deformation modes of the BEP are divided into three stages in succession from easy to difficult: C-type, Φ-type and S (B)-type deformation. This paper verifies that the compressive strength and energy absorption capacity of the GBEP increase by 35% and 87%, respectively, relative to those of the grid plate (GP) with the same volume. (2) Although the number of trabeculae of the GBEP is significantly less than that of the EBEP, each trabecula in the GBEP has one more honeycomb wall constraint than each trabecula in the EBEP. The increase range of the compressive properties of the GBEP relative to the GP is greater than that of the EBEP relative to the honeycomb plate (HP). This confirms the prediction that the compressive properties can be effectively improved by appropriately increasing the constraints on the trabeculae. This paper deepens and enriches the knowledge regarding the biomimetic application system of BEPs, lays the foundation for GBEPs, whose preparation is convenient, and accelerates the applications of GBEPs.

Influence Study of the Plastic Deformation Mode on the Micro-Indentation Mechanical Properties for the Pure Molybdenum

2021 ◽  
Vol 894 ◽  
pp. 39-43
Author(s):  
Jiang Li ◽  
Peng Fa Feng ◽  
Fu Guo Li ◽  
Qing Hua Li ◽  
Lin Lin Duan
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Powder Metallurgy ◽  
Deformation Mode ◽  
Indentation Hardness ◽  
Pure Molybdenum ◽  
Apparent Modulus ◽  
Deformation Instability ◽  
Deformation Modes ◽  
Micro Indentation

Four different plastic deformation modes of pure molybdenum in powder metallurgy were studied, including single tensile, single torsion, tensile-torsion and compressive-torsion. Then the influence of these four plastic deformation modes on the micro-mechanical properties of pure molybdenum in powder metallurgy was studied by the micro-indentation method. The results show that the accumulated strain before deformation instability or fracture of the studied material caused by different plastic deformation modes is different, while showing a regular variation. And the mean indentation hardness along the radial direction of the sample also change regularly, which results in different strengthening effects on the molybdenum material itself. The damage inside the deformed material will cause the apparent modulus of elasticity measured by micro-indentation to decrease significantly.

Development of Combined Machining Modes, Investigation of Mechanical Properties and Structure of Deformed Semi-Finished Products from Alloy 01417

2020 ◽  
Vol 992 ◽  
pp. 498-503
Author(s):  
S. Sidelnikov ◽  
D. Voroshilov ◽  
M. Motkov ◽  
M. Voroshilova ◽  
V. Bespalov
Keyword(s):  
Mechanical Properties ◽  
Rare Earth Metals ◽  
Electrophysical Properties ◽  
Intermediate Annealing ◽  
Plastic Properties ◽  
Bar Rolling ◽  
Annealing Temperatures ◽  
Continuous Ingot ◽  
The Wire ◽  
Deformation Modes

The article presents the results of studies on the production of wire with a diameter of 0.5 mm from aluminum alloy 01417 with a content of rare-earth metals (REM) in the amount of 7-9% for aircraft construction needs. The deformation modes, the experimental technique and equipment for the implementation of the proposed technology described. The wire was obtained by drawing and bar rolling with subsequent drawing from a rod with a diameter of 5 mm, obtained previously using the process of combined rolling-extruding (CRE) from a continuous ingot with a diameter of 12 mm, cast in an electromagnetic mold (EMM). The wire obtained by the presented technology was subjected to 4 different heat treatment modes with annealing temperatures from 350 to 500 °C and holding time of 1 h in the furnace to achieve mechanical and electrophysical properties corresponding to TS 1-809-1038-2018. The level of strength and plastic properties obtained in the course of research required only one intermediate annealing. The microstructure of the wire was investigated and the modes were revealed that made it possible to obtain the required level of mechanical properties and electrical resistivity, satisfying TS 1-809-1038-2018.

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