scholarly journals Deformation of high density polyethylene by dynamic equal-channel-angular pressing

RSC Advances ◽  
2018 ◽  
Vol 8 (40) ◽  
pp. 22583-22591 ◽  
Author(s):  
Xiangji Wu ◽  
Lin Pu ◽  
Yunfei Xu ◽  
Jinchun Shi ◽  
Xiaoyi Liu ◽  
...  
Keyword(s):  
Equal Channel Angular Pressing ◽  
High Density Polyethylene ◽  
High Density ◽  
Microstructure Changes ◽  
Angular Pressing

Dynamic equal-channel-angular pressing leads to macro- and microstructure changes of high density polyethylene.

Evolution of the crystalline and amorphous phases of high-density polyethylene subjected to equal-channel angular pressing

2019 ◽  
Vol 77 (4) ◽  
pp. 1681-1694 ◽  
Author(s):  
Majid Mokarizadeh Haghighi Shirazi ◽  
Mohammad Khajouei-Nezhad ◽  
Seyed Mojtaba Zebarjad ◽  
Ramin Ebrahimi
Keyword(s):  
Equal Channel Angular Pressing ◽  
High Density Polyethylene ◽  
High Density ◽  
Amorphous Phases ◽  
Angular Pressing

scholarly journals Experimental and Numerical Investigation of the ECAP Processed Copper: Microstructural Evolution, Crystallographic Texture and Hardness Homogeneity

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 607
Author(s):  
A. I. Alateyah ◽  
Mohamed M. Z. Ahmed ◽  
Yasser Zedan ◽  
H. Abd El-Hafez ◽  
Majed O. Alawad ◽  
...  
Keyword(s):  
Grain Size ◽  
Equal Channel Angular Pressing ◽  
Cross Section ◽  
Room Temperature ◽  
Pure Copper ◽  
High Density ◽  
Ecap Processing ◽  
Heterogeneous Distribution ◽  
Angular Pressing ◽  
Average Grain Size

The current study presents a detailed investigation for the equal channel angular pressing of pure copper through two regimes. The first was equal channel angular pressing (ECAP) processing at room temperature and the second was ECAP processing at 200 °C for up to 4-passes of route Bc. The grain structure and texture was investigated using electron back scattering diffraction (EBSD) across the whole sample cross-section and also the hardness and the tensile properties. The microstructure obtained after 1-pass at room temperature revealed finer equiaxed grains of about 3.89 µm down to submicrons with a high density of twin compared to the starting material. Additionally, a notable increase in the low angle grain boundaries (LAGBs) density was observed. This microstructure was found to be homogenous through the sample cross section. Further straining up to 2-passes showed a significant reduction of the average grain size to 2.97 µm with observable heterogeneous distribution of grains size. On the other hand, increasing the strain up to 4-passes enhanced the homogeneity of grain size distribution. The texture after 4-passes resembled the simple shear texture with about 7 times random. Conducting the ECAP processing at 200 °C resulted in a severely deformed microstructure with the highest fraction of submicron grains and high density of substructures was also observed. ECAP processing through 4-passes at room temperature experienced a significant increase in both hardness and tensile strength up to 180% and 124%, respectively.

Composition and Surface Topography Effects on Apatite-Forming Ability of Ceramic-Polymer Composites

2003 ◽  
Vol 774 ◽  
Author(s):  
Susan M. Rea ◽  
Serena M. Best ◽  
William Bonfield
Keyword(s):  
Surface Topography ◽  
High Density Polyethylene ◽  
High Density ◽  
Apatite Layer ◽  
Biologically Active ◽  
Human Blood Plasma ◽  
Apatite Formation ◽  
Polyethylene Matrix ◽  
Composite Surface ◽  
X Ray

AbstractHAPEXTM (40 vol% hydroxyapatite in a high-density polyethylene matrix) and AWPEX (40 vol% apatite-wollastonite glass ceramic in a high density polyethylene matrix) are composites designed to provide bioactivity and to match the mechanical properties of human cortical bone. HAPEXTM has had clinical success in middle ear and orbital implants, and there is great potential for further orthopaedic applications of these materials. However, more detailed in vitro investigations must be performed to better understand the biological interactions of the composites and so the bioactivity of each material was assessed in this study. Specifically, the effects of controlled surface topography and ceramic filler composition on apatite layer formation in acellular simulated body fluid (SBF) with ion concentration similar to those of human blood plasma were examined. Samples were prepared as 1 cm × 1 cm × 1 mm tiles with polished, roughened, or parallel-grooved surface finishes, and were incubated in 20 ml of SBF at 36.5 °C for 1, 3, 7, or 14 days. The formation of a biologically active apatite layer on the composite surface after immersion was demonstrated by thin-film x-ray diffraction (TF-XRD), environmental scanning electron microscopy (ESEM) imaging and energy dispersive x-ray (EDX) analysis. Variations in sample weight and solution pH over the period of incubation were also recorded. Significant differences were found between the two materials tested, with greater bioactivity in AWPEX than HAPEXTM overall. Results also indicate that within each material the surface topography is highly important, with rougher samples correlated to earlier apatite formation.

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