Resistance Of Workpiece Research Articles

Molecular dynamics for nanoindentation in the γ/α2 interfacial strengthening mechanism of a duplex full lamellar TiAl alloy

To investigate the effect of the γ/α2 interface on the deformation behavior and mechanical properties of the duplex all-sheet TiAl alloy during the nanoindentation process, simulations were carried out using molecular dynamics methods. The mechanical properties, atomic displacements, microscopic deformation behavior, stress-strain, and microstructure evolution patterns during nanoindentation are systematically analyzed. The results show that the movement of the atoms is impeded by the interface, directing them in a direction parallel to the interface and thus increasing the workpiece's resistance to deformation. The γ/α2 interface will prevent the propagation of dislocations, causing dislocation buildup, increasing the strength of the TiAl alloy and acting as a hardening agent. In addition, it has been found that the presence of interfaces impedes the transfer of stress and causes discontinuities in the stress distribution, the closer the region to the interface, the denser the distribution of high-stress strain atoms and the greater the concentration of the stress.

Experiment study on the corrosion resistance of the surface metamorphic layer of grinding

Workpiece will face corrosive problems during its application after the manufacturing process. As the common final process, grinding can generate special metamorphic layer on the surface of workpiece and change the initial corrosion resistance of workpiece. In order to study the corrosion resistance of workpiece after grinding process, the paper carries on combining experiment of grinding and electrochemical corrosion. The characteristic of corrosion resistance of grinding is revealed based on the association of grinding mechanism and electrochemical theory. The corrosion potential of workpiece after grinding is higher than matrix, which shows the grinding surface is difficult to begin to corrode. Electrochemical impedance spectroscopy (EIS) shows the grinding surface has large phase angle, impedance and capacitance characteristic because the metamorphic layer of grinding has good obstructive ability. They reveal that grinding improves the surface corrosion resistance of workpiece. Then the mechanism of the corrosion resistance of grinding is revealed. The special grain boundary formed in grinding with much C element, large clusters and complex shape prolongs the corrosion channel, which reduces the corrosive speed. While, the sensitive hardening structure generated in grinding hardening with much free energy is easy to form the corrosion cell, which will accelerate the corrosion.

Life time improvement of D7 tool steel by cryogenic treatment

Abstract Heat treatment is generally carried out in tool steels to achieve desired results. They are widely used than Cold treatment. Cold treatment is less much competitive to heat treatment which often gives better results. It is also said to be cryogenic process where it is treated at very low temperatures. The phase transformation of material takes place which improves properties of tool. The influence of treatment done using cryogenic on friction and wear behavior of AISI D7 steel tool is investigated. In cryogenic tool, the resistance of work piece is low due to the increase in hardness of the tool.