EXPERIMENTAL STUDY ON INTERFACE STRENGTH OF MICRO/NANO-MATERIALS AND THEIR STRUCTURES

This paper reviewsrecent advances in experimental studies on mechanical strength ofsmall materials with micro- to nano-meter scales. In particular,experimental systems and some testing methods developed by thecurrent authors are introduced for measuring the interfacestrength in small materials and low-dimensional tiny components,and main experimental results are presented as well. The testingmethods discussed are: (1) sandwiched cantilever method forevaluating the initiation strength of an interface crack insubmicron films deposited on substrates, (2) modified AFM methodfor measuring the interface bonding strength between nano-islandsand substrates, (3) pre-cracking technique for measuring crackgrowth along the interface, (4) a crack initiation method fornano-components using special loading apparatus built in a TEM andcapable of in-situ observing the process of crack growth, (5)modified four-point bend method for measuring sub-critical crackgrowth along an interface between submicron films under fatigue,and (6) a special testing method for creep crack growth along aninterface between polymeric film and glass substrate. From theresults obtained, the authors pointed out the merits of the aboveexperimental methods and their limitations. Meanwhile, the mainchallenges and difficulties in testing the interface strength ofmicro- to nano-materials and such tiny structures aredemonstrated, and several future research topics are outlined.