Study on fracture toughness of commercially pure titanium based on small punch test
HAO Long
DAI Qiao
LI Jun
Abstract：[Objective]Conventional fracture tests require a large amount of test material,which is difficult to obtain from in-service titanium equipment.To address this issue,a method for determining material fracture toughness using miniature specimens was established based on the small punch test,providing a reference for material performance evaluation of in-service equipment.[Methods]Firstly,standard fracture toughness tests were carried out on commercially pure titanium TA2 to acquire its fracture toughness.Secondly,small punch tests were performed.The effects of notch length on the fracture process of small punch specimens were investigated by analyzing fracture morphologies,load-displacement curves and absorbed energy.Finally,the fracture toughness of TA2 was determined via an energy difference method derived from small punch test data.[Results]The results show that as notch length increases,the maximum load borne by small punch specimens decreases,the displacement at maximum load rises,and the energy consumed during testing increases.In addition,the failure mode is dependent on notch length.Specimens without notches and those with a 4.5 mm notch fail via circumferential fracture,specimens with 5 mm and 5.5 mm notches experience crack propagation fracture along the notch direction,while specimens with a 6 mm notch undergo overall notch deformation failure.When evaluating material fracture properties using small punch tests,if side-notched specimens fail by crack propagation along the notch,the fracture performance of the material can be reliably characterized using the energy difference obtained from specimens with different notch lengths.
Keywords：Commercial pure titanium TA2Small punch testNotched specimenFailure modeFracture toughness
Publication Date：2026-07-31
Online Publishing Date：2026-09-12(First online date of this platform, not the publication date of the document)
Pages：8( 94-101 )