TY - JOUR

T1 - Design and Evaluation of an Experimental Technique for Mechanical and Fatigue Testing of Sub-Sized Samples

AU - Lomakin, I. V.

AU - Arutyunyan, A. R.

AU - Valiev, R. R.

AU - Gadzhiev, F. A.

AU - Murashkin, M. Yu

PY - 2018/6/1

Y1 - 2018/6/1

N2 - Some recently developed processing techniques allow fabrication of small specimens. The fatigue behavior of these small samples cannot be characterised according to the existing standards due to size limitations. The main objective of the present work is to develop an original technique for both mechanical and fatigue testing of sub-sized specimens produced by a high pressure torsion (HPT) method. The fatigue behavior of the sub-sized Ti-6Al-4 V samples, made from HPT-processed disks, is compared with that of the standard samples prepared according to the ASTM standards. Finite element method (FEM) analysis of the stress distribution under applied static load, for both sub-sized specimens and grips designed for their testing, is performed. Good agreement between the outcomes of tensile testing of the standard ASTM samples and sub-sized samples is observed. Fatigue data, represented by Wöhler curves for both types of samples, showed significant divergence of high cycle fatigue properties caused by incompliance of specimen geometries and surface/defect size ratio. The obtained results can be used to scale up the fatigue behavior from sub-sized specimens to the standard ones, as well as to predict the fatigue behavior of the bulk nanostructured metals and alloys produced by HPT.

AB - Some recently developed processing techniques allow fabrication of small specimens. The fatigue behavior of these small samples cannot be characterised according to the existing standards due to size limitations. The main objective of the present work is to develop an original technique for both mechanical and fatigue testing of sub-sized specimens produced by a high pressure torsion (HPT) method. The fatigue behavior of the sub-sized Ti-6Al-4 V samples, made from HPT-processed disks, is compared with that of the standard samples prepared according to the ASTM standards. Finite element method (FEM) analysis of the stress distribution under applied static load, for both sub-sized specimens and grips designed for their testing, is performed. Good agreement between the outcomes of tensile testing of the standard ASTM samples and sub-sized samples is observed. Fatigue data, represented by Wöhler curves for both types of samples, showed significant divergence of high cycle fatigue properties caused by incompliance of specimen geometries and surface/defect size ratio. The obtained results can be used to scale up the fatigue behavior from sub-sized specimens to the standard ones, as well as to predict the fatigue behavior of the bulk nanostructured metals and alloys produced by HPT.

KW - Experimental technique

KW - Fatigue life

KW - Finite element analysis

KW - Fractography

KW - Sub-sized specimen

KW - Ti-6Al-4V alloy

KW - GRAIN-REFINEMENT

KW - Ti-6Al-4Valloy

KW - HIGH-PRESSURE TORSION

KW - BEHAVIOR

KW - HPT

KW - PRINCIPLES

KW - ECAP-CONFORM

KW - ALUMINUM-ALLOY

KW - STEEL

KW - SEVERE PLASTIC-DEFORMATION

KW - EXTRUSION

UR - http://www.scopus.com/inward/record.url?scp=85046675795&partnerID=8YFLogxK

U2 - 10.1007/s40799-017-0229-7

DO - 10.1007/s40799-017-0229-7

M3 - Article

AN - SCOPUS:85046675795

VL - 42

SP - 261

EP - 270

JO - Experimental Techniques

JF - Experimental Techniques

SN - 0732-8818

IS - 3

ER -