Cyclic extrusion compression angular pressing (CECAP) is a novel severe plastic deformation (SPD) method applied to improve the mechanical and metallurgical properties of materials. In this research, finite element analysis and response surface method were considered for CP-Ti in CECAP process. Temperature, input extrusion diameter, exit extrusion angle, shear factor and longitudinal distance of input extrusion to the ECAP region were selected as input parameters to study strain distribution in the current process. The analysis of variance (ANOVA) was developed for current work, and the results showed that input parameters of input extrusion diameter and shear factor, and the interaction of the temperature and longitudinal distance of input extrusion to ECAP region, and the shear factor and longitudinal distance of input extrusion to ECAP region considerably affect the strain distribution. Hardness measurement in section A at the points near the center and outer surfaces of the sample showed the hardness of 21 and 24 HRC respectively. At this point, the maximum difference for hardness was achieved at about 12% throughout the cross section which is in suitable agreement with the strain distribution model. Moreover, the optical microscope (OM), both current CDECAP and conventional CECAP, showed that the majority of deformed grains were enlarged. The average deformed grain size for the current CECAP was reduced to 100 nm, which is considerably smaller than the conventional CECAP with an average grain size of 300 nm. Furthermore, the load-stroke diagram was achieved by executing experimental tests and comparing the results achieved the numerical model. The results showed a good agreement between them.

In this work, the strength of the cold roll bond of the commercially pure titanium (CP Ti) sheet and the effect of TiO2 nanoparticles on the bond strength were investigated. Through the accumulative roll bonding process, which is considered one of the important severe plastic deformation processes, the creation of suitable bonds can play a significance role in the ultimate strength of the bond. Thus, at first the optimum bonding parameters of two or several metals producible via ARB method were studied and then manufactured. In the present work, the bond strength of the commercially pure titanium sheets was investigated. Based on the results of the peeling test for CP Ti it was found that by applying a 50% thickness reduction, a desirable bond strength was achieved. To study the effect TiO2 nanoparticles on nanocomposite preparation in the ARB test, these nanoparticles were dispersed between the CP Ti sheets at 0.1, 0.3 and 0.5wt% concentrations. The results showed a decrease in the bond strength during the peeling test by the increase in the TiO2 content. The scanning electron microscopy (SEM) tests of the peeled sites revealed that the presence of cumulative layers of nanoparticles prevented bonding in these areas. Although the addition of TiO2 nanoparticles resulted in the reduced bond strength, at TiO2 percentages equal or less than 0.5wt.%, this decrease was negligible. Hence, the ARB method could be considered as an efficient technique for the preparation of the bulk composite at room temperature.

In the present study, a novel combined process of severe plastic deformation (SPD) process was introduced, and its effects on the flow behavior, workability, and mechanical properties of commercially pure titanium were investigated through a single-pass billet deformation. The process consists of three sequential stages: primary cyclic extrusion compression (CEC), equal channel angular pressing (ECAP), and final extrusion. The results showed that the average hardness of the annealed, as-received specimens was 14 HRC on the section perpendicular to the movement axis. This value increased to 21 HRC, 26 HRC, and 29.5 HRC in samples processed by ECAP, CECAP, and the New CECAP process, respectively. These results demonstrate the superior effectiveness of the New CECAP process in enhancing hardness. Moreover, the findings revealed that the New CECAP process improves the strain distribution compared to CECAP and ECAP, with maximum strain increasing by up to 15% and 23%, respectively.

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Let Cc(X) be the functionally countable subalgebra of C(X). Essential CP-spaces are introduced and investigated algebraically and topologically. It is shown that if X is a proper essential CP-space, then mCc(X) is compact if and only if f, g is a G, , where ,is the only non CP-point of X and mCc(X) is the space of minimal prime ideals of Cc(X) which are not maximal. Quasi Fc-spaces, c-basically disconnect spaces, almost CP-spaces and almost essential CP-spaces are introduced and studied via essential CP-spaces. Finally, Cc(X) as a CSV-ring where X is an essential CP-space is investigated.