Search

Friction surface stirring (FSS) was employed to enhance the tribological properties of commercially pure Ti (CP-Ti). Applying FSS under the optimised process parameters (i.e. rotation and traverse speeds of 100 rpmand 8mm/min, respectively) was found to increase the surface hardness of as-received CP-Ti from about 200--630 HV. The sliding wear resistance was therefore increased by 76, 76, and 85% under applied loads of 5, 10, and 20 N, respectively. The average friction coefficient (AFC) of CP-Ti also reduced considerably by the FSS. For instance, the AFC was reduced from 0.67±0.07 and 1.04±0.14 to about 0.33±0.03 and 0.45±0.04 at the applied loads of 5 and 20 N, respectively. The wear and friction mechanisms were also discussed. [ABSTRACT FROM AUTHOR]

In this research, dissimilar joints between copper and stainless steel 316by gas-tungsten arc welding using copper and monel filler metals and also the similar welding of steel 316 have been investigated. The microstructure was studied by OM, SEM and EDS. Tensile and impact tests were done to evaluate the mechanical properties. In order to investigate the sigma phase formation, the specimens were heat treated. The microstructure of the dissimilar welds contained an iron rich and a copper or monel phase. After heat treatment, no sigma phase was observed in the dissimilar joint that it seems that the presence of copper and nickel as an austenite stabilizer elements in the microstructure prevents the sigma phase formation. [ABSTRACT FROM AUTHOR]