The deformation behavior of bulk ZnO single crystals is studied by a combination of spherical nanoindentation and atomic force microscopy. Results show that ZnO exhibits plastic deformation for relatively low loads ~*4–13 mN with an ;4.2 mm radius spherical indenter!. Interestingly, the elastic–plastic deformation transition threshold depends on the loading rate, with faster loading resulting, ...

The plastic deformation of Ti45Zr16Be20Cu10Ni9 bulk metallic glass has been investigated by nanoindentation performed with loads ranging from 10 to 200 mN in a wide range of loading rates. The plastic flow in the alloy exhibited conspicuous serrations at low loading rates. The serrations, however, became less prominent as the rate of indentation increased. Atomic force microscopy showed a signi...

To produce carbonate apatite (CAP) ceramics with the desired complex shapes using superplastic deformation, deformation behavior of CAP ceramics under constant loading as well as physical properties after deformation were evaluated. Sintered CAP ceramics were plastically deformed in an electric furnace attached to a universal hydraulic testing machine under a constant load. CAP ceramics subject...

A method was developed for creating single well-defined surface asperities using an imprint technique. The proposed enables:•Creation of micrometre high asperities•Creation which survived more than 35 million EHL contact cycles•Damage tracing thanks to the possibility control damage initiation sites.The technique is based on rolling a hard disc with indents against soft asperities. pressure cau...

The results from experimental research of deformation by upsetting and die forging of lead specimens wit controlled impact are presented. Laboratory setup for conducting the investigations, which uses cold rocket engine operated with compressed air, is described. The results show that when using controlled impact is achieving greater plastic deformation and consumes less impact energy than at o...

In this paper, accumulation of plastic deformation of AISI 1045 steel plates with circular cutouts under cyclic axial loading is studied. Loading was applied under force-control conditions. Experimental tests were performed using a Zwick/Roell servo hydraulic machine. Under force-control loading with nonzero mean force, plastic strain was accumulated in continuous cycles called ratcheting. Nume...

NiTi wires were brazed together via eutectic reaction between NiTi and Nb powder deposited at the wire contact region. Phase transformation and deformation behavior of the NiTi-Nb eutectic microstructure were investigated using transmission electron microscopy (TEM) and cyclic loading-unloading tests. Results show that R phase and B19' martensite transformation are induced by plastic deformatio...

Ratcheting behavior of steel 304L cylindrical shell under cyclic combined and axial loading are investigated in this paper, numerically. Cylindrical shells were fixed oblique at angle of 20° and normal with respect to the longitudinal direction of the shell and subjected to force-controlled cycling with non-zero mean force, which causes the accumulation of plastic deformation or ratcheting beha...

This paper investigates the plastic deformation in mono-crystalline silicon under complex loading conditions. With the aid of various characterization techniques, it was found that the mechanism of plasticity in silicon is complex and depends on loading conditions, involving dislocations, phase transformations and chemical reactions. In general, plastic deformation in silicon is the coupled res...

True stress (·)­true strain (3⁄4) relationships until just before fracture, i.e., the plastic deformation limit, were estimated by the stepwise tensile test and the Bridgman equation for various metals and alloys with different crystal structures. The estimated ·­3⁄4 relationships were different from the nominal stress­strain curves including the conventional tensile properties. In the relation...