scholarly journals Effect of ECAP Die Angle on Mechanical Properties and Biocompatibility of SS316L

Metals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1513
Author(s):  
Dayangku Noorfazidah Awang Sh’ri ◽  
Zahiruddeen Salam Zahari ◽  
Akiko Yamamoto

In this study, ultrafine grain (UFG) SS316L was produced using an equal channel angular pressing (ECAP) process at two different die angles namely 120° and 126°. The effect of different die angles on mechanical, corrosion, and surface properties were thoroughly investigated. Furthermore, the subsequent effect on the cytotoxicity of SS316L was investigated. The microstructure observation shows ECAP processing has produced an elongated, finer grain size at 120° than 126°. The ECAP processing also increases the hardness of SS316L. There is no change in wettability and surface roughness observed. However, the ectrochemical measurement reveals that ECAP processing improves the corrosion resistance of SS316L. The cytocompatibility of ECAPed SS316L was evaluated by both a direct and an extract methods, finding the contribution of grain refinement by ECAP processing.

2013 ◽  
Vol 58 (2) ◽  
pp. 481-487 ◽  
Author(s):  
K. Bryła ◽  
J. Dutkiewicz ◽  
L.L. Rokhlin ◽  
L. Litynska-Dobrzynska ◽  
K. Mroczka ◽  
...  

The influence of ageing and Equal Channel Angular Pressing (ECAP) on the microstructure and mechanical properties of Mg-2.5%Tb-0.78%Sm alloy has been examined. The microhardness changes during ageing at 200ºC show a slight increase. The aged microstructure at maximum hardness contains Mg12(Tb,Sm) - metastable β’ phase of size about 2-10 nm as dispersed precipitates. The orientation relationship between β’ phase and the matrix was found as follows:(0001)Mg || (1¯10)β′, [21¯10]Mg || [116]β′. The ECAP passes were performed by two procedures: “I” - four passes at 350ºC; “II” - one pass at 370ºC, second pass at 340ºC and third pass at 310ºC. The grain size was reduced about 200 times as a results of ECAP process according “I” and “II” procedure. The grain refinement by ECAP improves significantly the compression yield strength and hardness. The Hall-Petch relationship was confirmed basing on microhardness measurements and the grain size after ECAP. The Mg24(Tb,Sm)5 and Mg41(Sm,Tb)5 particles smaller than 150 nm are located mainly at grain and subgrain boundaries and they prevent grain growth during ECAP processing. The microstructure evolution during ECAP can be described as dynamic recovery and continuous and discontinuous dynamic recrystallization.


2021 ◽  
Author(s):  
Serkan Öğüt ◽  
Hasan Kaya ◽  
Aykut Kentli ◽  
Mehmet UÇAR

Abstract Equal channel angular pressing (ECAP), expansion equal channel angular pressing (Exp.-ECAP) and hybrid equal channel angular pressing (HECAP) processes were applied to pure copper specimens within this study. Before the ECAP and HECAP processes, an Exp.-ECAP mold with optimum geometric parameters was produced to be used in these processes. The samples, on which ECAP, Exp.-ECAP and HECAP processes were applied, were subjected to microstructure analysis and mechanical tests, and the effects of these processes were examined. The results obtained showed that the Exp.-ECAP process gave better results in grain refinement and mechanical properties, and the Exp.-ECAP passes applied after the ECAP process within the scope of the HECAP process provided a more homogeneous distribution for grain size and hardness.


2020 ◽  
Vol 402 ◽  
pp. 67-72
Author(s):  
Rahmawaty ◽  
Surya Dharma ◽  
Abdul Razak ◽  
Sarjianto ◽  
Nisfan Bahri ◽  
...  

Equal-channel angular pressing (ECAP) is an effective fabrication process to modify ultrafine grain size. It is believed that the smaller grain size could improve the mechanical properties. In the present work, the solution treatment applied to Al-Si-Cu-Mg-Mn alloy. Furthermore, two models of ECAP have been done through one-to-three pass at room temperature. The microstructures were observed by optical microscope (OM) and scanning electron microscope (SEM). The micro-hardness of longitudinal plane was analyzed by vickers hardness test. The strength of ECAP materials at room temperature was obtained by using tensile test. The results show that the ECAP process has improved mechanical properties of alloys, which were the hardness and ultimate tensile strength tend to increase since single pass stage.


Metalurgi ◽  
2021 ◽  
Vol 36 (2) ◽  
Author(s):  
Vinda Puspasari ◽  
I. Nyoman Gede P. A. ◽  
Efendi Mabruri ◽  
Satrio Herbirowo ◽  
Edy Priyanto Utomo

Al-Mg-Si alloys (6xxx) has been widely used as structural materials in building and vehicles because of its excellent strength and corrosion resistance. The improvement of fine grain microstructure which can increase mechanical and physical properties become an interesting field in recent research.. Equal channel angular press is the most promising method to apply severe plastic deformation (SPD) which can produce ultra-fine grain in the bulk material without residual porosity. This study presents some experiments results on the effect of ECAP number of passes variation to the hardness, microstructure, and corrosion behaviour of Al 6061 alloys. The samples were annealed in the furnace with argon gas environment at 530°C for 4 hours and then immersed in liquid nitrogen for 5 minutes before ECAP process. The ECAP process was done with Bc route using dies with 120° of internal channel angle and pass variation of 1, 2, 3, and 4. The optimum hardness is 107.58 HRB in Al 6061 samples with 3 passes of ECAP. The increasing ECAP number of passes leads to a significant grain size reduction from 0 way pass, the grain size is around 10 µm, while for a 4 way pass, the grain size is around 2.5 µm. The corrosion resistance of Al 6061 alloys increased with the increasing number of passes in ECAP process.


2013 ◽  
Vol 586 ◽  
pp. 100-103 ◽  
Author(s):  
Jiří Buršík ◽  
Vilma Buršíková ◽  
Milan Svoboda ◽  
Petr Král ◽  
Jiří Dvořák ◽  
...  

Microstructure of Cu-2wt.%Co alloy after various heat treatment (and hence with various phase constitution) was studied after equal-channel angular pressing (ECAP) using transmission electron microscopy (TEM) and electron backscatter diffraction (EBSD) technique in a scanning electron microscope (SEM). We also focused on local mechanical properties measured across the section perpendicular to the ECAP extrusion direction. Starting from the grain size well above 1mm in the Cu-2wt.%Co solid solution, ECAP subsequently reduces grain size down to the submicron level. A comparison with pure Cu shows that the grain size homogenization is shifted towards higher number of ECAP passes. Fine dispersion of precipitates further slows down the grain refinement and grain size homogenization during ECAP processing. Local mechanical properties measured across the section perpendicular to the ECAP extrusion direction reveal systematic inhomogeneities of deformed microstructure caused by local gradients of temperature and pressure and by the processing geometry itself. This should be considered while characterizing the microstructure by a single EBSD measurement on a small selected area.


2013 ◽  
Vol 717 ◽  
pp. 9-14 ◽  
Author(s):  
P.M. Ajith ◽  
P. Sathiya ◽  
Kondaiah Gudimetla ◽  
B. Ravishankar

Duplex Stainless Steel (DSS) is well known for their higher mechanical strength and better corrosion resistance. DSS is commonly used for marine construction, petrochemical and chemical industries. DSS (2205) is having equal amount of α and γ phases.The present study was conducted on12mm diameter rod of the UNS S32205 duplex stainless steel subjected to equal channel angular pressing (ECAP). The refinement of original grains was observed. Effect of microstructure change on the corrosion behavior of equal channel angular pressed (ECAP) UNS S32205 duplex stainless steel was investigated. After single pass ECAP process and study about the pitting corrosion resistance. The mechanical properties of UNS S3 2205 duplex stainless steelwere evaluated. The amount of ferrite after ECAP and before ECAP for the two different conditions was investigated. Also observed percentage of ferrite content reduces 3.32% after ECAP.


2012 ◽  
Vol 268-270 ◽  
pp. 291-296
Author(s):  
Li Min Wang ◽  
Zhi Hua Gong ◽  
Gang Yang ◽  
Zheng Dong Liu ◽  
Han Sheng Bao

Ultrafine-grain or even nano-grain microstructure can be made by equal channel angular pressing (ECAP), mainly resulting from shear strain. The authors experimentally investigated 00Cr18Ni12 austenitic stainless steel and its mechanical properties during and after ECAP. The results showed that because of larger shear stress, many slipping bands occured inside grains, with the increase of pressing pass, the slipping bands may interact with each other to separate slipping bands into sub-grains, finally, the sub-grains transformed into new grains with large angular boundaries. The grain size was about 200nm after the 7th pass. After the 1st and 2nd pass, the tensile strength was higher 93% and 144% than that without ECAP, the yield strength was 5.3 and 6.6 times of that without ECAP respectively.


2021 ◽  
Vol 104 (2) ◽  
pp. 003685042110294
Author(s):  
Khaled Abd El-Aziz ◽  
Emad M Ahmed ◽  
Abdulaziz H Alghtani ◽  
Bassem F Felemban ◽  
Hafiz T Ali ◽  
...  

Aluminum alloys are the most essential part of all shaped castings manufactured, mainly in the automotive, food industry, and structural applications. There is little consensus as to the precise relationship between grain size after grain refinement and corrosion resistance; conflicting conclusions have been published showing that reduced grain size can decrease or increase corrosion resistance. The effect of Al–5Ti–1B grain refiner (GR alloy) with different percentages on the mechanical properties and corrosion behavior of Aluminum-magnesium-silicon alloy (Al–Mg–Si) was studied. The average grain size is determined according to the E112ASTM standard. The compressive test specimens were made as per ASTM: E8/E8M-16 standard to get their compressive properties. The bulk hardness using Vickers hardness testing machine at a load of 50 g. Electrochemical corrosion tests were carried out in 3.5 % NaCl solution using Autolab Potentiostat/Galvanostat (PGSTAT 30).The grain size of the Al–Mg–Si alloy was reduced from 82 to 46 µm by the addition of GR alloy. The morphology of α-Al dendrites changes from coarse dendritic structure to fine equiaxed grains due to the addition of GR alloy and segregation of Ti, which controls the growth of primary α-Al. In addition, the mechanical properties of the Al–Mg–Si alloy were improved by GR alloy addition. GR alloy addition to Al–Mg–Si alloy produced fine-grained structure and better hardness and compressive strength. The addition of GR alloy did not reveal any marked improvements in the corrosion properties of Al–Mg–Si alloy.


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 ◽  
...  

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.


2012 ◽  
Vol 468-471 ◽  
pp. 2124-2127 ◽  
Author(s):  
Shao Feng Zeng ◽  
Kai Huai Yang ◽  
Wen Zhe Chen

Equal channel angular pressing (ECAP) was applied to a commercial AZ61 magnesium alloy for up to 8 passes at temperatures as low as 473K. Microstructures and mechanical properties of as-received and ECAP deformed samples were investigated. The microstructure was initially not uniform with a “bimodal” grain size distribution but became increasingly homogeneous with further ECAP passes and the average grain size was considerably reduced from over 26 μm to below 5 μm. The ultimate tensile strength (UTS) decreases clearly after one pass, but increases significantly up to two passes, and then continuously slowly decreases up to six passes, and again increases slightly up to eight passes. In contrast, the uniform elongation increased significantly up to 3 passes, followed by considerable decrease up to 8 passes. These observations may be attributed to combined effects of grain refinement and texture development.


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