Effect of low temperature rolling on mechanical properties and corrosion resistance of CrCoNi medium entropy alloy

Abstract: For the casted CrCoNi medium entropy alloy melted by magnetic levitation, the deformation was carried out in 4 passes under the condition of liquid nitrogen temperature (-196°C), the total reduction was 50%,The microstructure and properties were analyzed after liquid nitrogen low temperature rolled. The experimental data showed that the phase structure of the alloy was not changed under the low-temperature rolling. The grains, crushed and refined, were elongated along the rolling direction. With the increasing of passes and reduction, the tensile strength increased from 585 MPa to 1359 MPa, while the elongation decreased from 37.8% to 5.9%. work With the increasing of work hardening,the tensile strength of the CrCoNi medium entropy alloy gradually increased, while the plasticity dramatic decreased. At the same time,the corrosion resistance of the CrCoNi medium entropy alloy was improved by low temperature cold rolled. The corrosion resistance of as-cast and rolled CrCoNi was much better than 304 stainless steel.

Microstructure and properties evolution of Mg–2Y–0.6Nd–0.6Zr alloy rolled at room and liquid nitrogen temperature

The microstructure evolution, texture, mechanical behavior and twin deformation of the ECAPed Mg–2Y–0.6Nd–0.6Zr alloy at room and liquid nitrogen temperature were investigated by rolling samples. The ECAP processed material appeared the texture of 45° to the extrusion direction and its yield strength reached 93.6 MPa. The results showed that cryorolling encourages twinning in Mg–2Y–0.6Nd–0.6Zr alloy, enhancing the tensile strength and texture. Activation of {10–12} twinning during rolling was found to be more pronounced in the cryorolled samples than in the cold rolled samples owing to a lower temperature. As a result, the cryorolled samples had more twins than and cold rolled ones, the proportion of twin areas of room temperature rolling and ultra-low temperature rolling were: 2.45% and 4.23%.

Microstructure Evolution of Mg-2Y-0.6Nd-0.6Zr Alloy Rolled at Room and Liquid Nitrogen Temperature

The microstructure evolution, texture, mechanical behavior and twin deformation of the ECAPed Mg-2Y-0.6Nd-0.6Zr alloy at liquid nitrogen temperature were investigated by rolling samples. The ECAP processed material appeared the texture of 45 ° to the extrusion direction and its yield strength reached 93.6 MPa. The results showed that cryorolling encourages twinning in Mg-2Y-0.6Nd-0.6Zr alloy, enhancing the tensile strength and texture. Activation of {10-12} twinning during rolling was found to be more pronounced in the cryorolled samples than in the cold rolled samples owing to a lower temperature. As a result, the cryorolled samples had more twins than and cold rolled ones, the proportion of twin areas of room temperature rolling and ultra-low temperature rolling were: 2.445% and 4.234%.

Study of Microstructure and Mechanical Properties of Hot-Rolled Ultra-High Strength Ferrite-Bainite Dual Phase Steel

Effects of thermo-mechanical control processing (TMCP) on microstructure and mechanical properties of hot-rolled ultra-high strength ferrite-bainite dual phase steel were investigated on a laboratory hot rolling mill. The results have shown that the microstructure containing ferrite and bainite can be obtained by TMCP. Ultimate tensile strength of all the specimens exceeded 1000MPa. Finish rolling temperatures affect the mechanical properties of ultra-high strength ferrite-bainite dual phase steel. Ultimate tensile strength reached 1078MPa at relatively low finish rolling temperature because of the ferrite grains refined. Fast cooling after low temperature rolling results in the ferrite grains refined and the formation of martensite islands. As a result, the product of ultimate tensile strength and total elongation (Rm×A50) of specimen 4 with fast cooling after low temperature rolling reaches the maximum value (18096MPa%).

Microstructures and Precipitates in High Purified Fe- 17 wt% Cr Alloy Steels

In the present paper, the influences of rolling temperatures on microstructure and precipitate in high purified Fe- 17 wt% Cr alloy steels were investigated by conventional process and low temperature rolling process. The hot rolled bands were annealed, cold rolled and annealed in the same processes. By means of optical microscopy observations, transmission electron microscopy analyses and thermodynamic calculations, the microstructural evolutions were studied and compared. It was shown that low temperature rolling process resulted in the refined rolling and annealing microstructure; Low temperature rolling process could form more fine TiC precipitates than in the conventional process due to the occurrence of strain-induced precipitation. These results have been confirmed by the thermodynamic calculations.