Influence of stress corrosion on the mechanical properties of laser-welded titanium

Abstract Statement of problem Whether laser-welded (LW) titanium can resist the stress corrosion produced by the combination of fluoride ions and stress in the oral environment is unknown. Purpose The purpose of this in vitro study was to investigate the influence of stress corrosion on the mechanic...

Full description

Saved in:
Bibliographic Details
Published in:The Journal of prosthetic dentistry 2016-03, Vol.115 (3), p.356-362
Main Authors: de Assis Ferreira, Nancy, DDS, MS, PhD, Senna, Plinio Mendes, DDS, MS, PhD, do Lago, Dalva Cristina Baptista, MChem, PhD, de Senna, Lilian Ferreira, MChem, PhD, Sampaio-Filho, Helio Rodrigues, DDS, MS, PhD
Format: Article
Language:English
Subjects:
Corrosion
Dentistry
Lasers
Materials Testing
Microscopy, Electron, Scanning
Saliva, Artificial
Stress, Mechanical
Surface Properties
Titanium - chemistry
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Abstract Statement of problem Whether laser-welded (LW) titanium can resist the stress corrosion produced by the combination of fluoride ions and stress in the oral environment is unknown. Purpose The purpose of this in vitro study was to investigate the influence of stress corrosion on the mechanical properties of LW titanium. Material and methods Twenty-seven titanium bars (25×2 mm) with a circular cross-section were cut in half and laser-welded, while another 27 nonwelded (NW) bars were used as the control. Thirty bars were submitted to a flexural load of 480 N at 1 Hz and immersed in artificial saliva at pH 6 (S1) or in 1000 ppm fluoride-containing saliva at pH 6.0 (S2) or 2.0 (S3) at room temperature for up to 4000 cycles. After the stress corrosion simulation, the tensile strength and Vickers microhardness were determined (n=5). Twelve LW and NW bars were submitted to the corrosion immersion test media for 51 days (n=2) to determine polarization curves (n=2) in an artificial saliva media. The corroded surface was examined with scanning electron microscopy (SEM). Results The combination of fluoride and low pH significantly decreased the tensile strength of LW ( P .05). NW bars immersed in S3 exhibited progressive surface dissolution, while LW bars spontaneously fractured at the welded area after 25 days of immersion in the same medium. SEM images demonstrated pitting corrosion without the presence of cracks in both groups immersed in S3. Conclusions Stress corrosion caused by acidic fluoride-containing saliva and flexural load cycling decreased the tensile strength and hardness of LW titanium bars.
ISSN:0022-3913
1097-6841
DOI:10.1016/j.prosdent.2015.09.002