Journal of Non-Crystalline Solids, ( ISI ), Volume (533), No (1), Year (2020-4) , Pages (119904-13)

Title : ( Non-isothermal crystallization kinetics investigation of different zones at the joining area of a bulk metallic glass welded by friction stir spot welding (FSSW) )

Authors: Zahra Jamili-Shirvan , Mohsen Haddad Sabzevar , Jalil Vahdati Khaki , Ke-Fu Yao ,

Citation: BibTeX | EndNote

Abstract

The connection cross section of a Ti-based bulk metallic glass welded with friction stir spot welding method, was investigated using Vickers micro-hardness and SEM. Regarding the results, four zones were detected at the connection site. The crystallization kinetics of the four zones identified at the joining area, was studied using the DSC at heating rates of 10–50 K min−1. Apparent activation energy (Ec), frequency factor (A) at characteristic temperatures (Tg, Tx1, Tp1) and local activation energy (Ec(α)) variations of different zones during the first crystallization transformation were calculated by isokinetics and isoconversional models. The crystallization conversion function for each zone was determined using the Sestak-Berggren equation. Sub-tool tip stir zone (TSZ) showed the highest thermal stability. The thermo-mechanically affected zone (TMAZ) with the highest onset crystallization temperature (Tx1) has a higher thermal stability in comparison to sub-tool shoulder stir zone (SSZ) with the lowest thermal stability and base metal (BM).The connection cross section of a Ti-based bulk metallic glass welded with friction stir spot welding method, was investigated using Vickers micro-hardness and SEM. Regarding the results, four zones were detected at the connection site. The crystallization kinetics of the four zones identified at the joining area, was studied using the DSC at heating rates of 10–50 K min−1. Apparent activation energy (Ec), frequency factor (A) at characteristic temperatures (Tg, Tx1, Tp1) and local activation energy (Ec(α)) variations of different zones during the first crystallization transformation were calculated by isokinetics and isoconversional models. The crystallization conversion function for each zone was determined using the Sestak-Berggren equation. Sub-tool tip stir zone (TSZ) showed the highest thermal stability. The thermo-mechanically affected zone (TMAZ) with the highest onset crystallization temperature (Tx1) has a higher thermal stability in comparison to sub-tool shoulder stir zone (SSZ) with the lowest thermal stability and base metal (BM).

Keywords

, Bulk metallic glass Friction stir spot welding Different zones of the weld spot Non, isothermal crystallization kinetics
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@article{paperid:1081548,
author = {Zahra Jamili-Shirvan and Haddad Sabzevar, Mohsen and Vahdati Khaki, Jalil and Ke-Fu Yao},
title = {Non-isothermal crystallization kinetics investigation of different zones at the joining area of a bulk metallic glass welded by friction stir spot welding (FSSW)},
journal = {Journal of Non-Crystalline Solids},
year = {2020},
volume = {533},
number = {1},
month = {April},
issn = {0022-3093},
pages = {119904--13},
numpages = {-119891},
keywords = {Bulk metallic glass Friction stir spot welding Different zones of the weld spot Non-isothermal crystallization kinetics},
}

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%0 Journal Article
%T Non-isothermal crystallization kinetics investigation of different zones at the joining area of a bulk metallic glass welded by friction stir spot welding (FSSW)
%A Zahra Jamili-Shirvan
%A Haddad Sabzevar, Mohsen
%A Vahdati Khaki, Jalil
%A Ke-Fu Yao
%J Journal of Non-Crystalline Solids
%@ 0022-3093
%D 2020

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