Incremental equal channel angular pressing (I-ECAP) is one of the continuous severe plastic deformation (SPD) processes. This paper presents the processing of commercial purity titanium (CP-Ti) using a double billet variant of I-ECAP process. Ultrafine-grain (UFG) structure was successfully achieved after six passes of I-ECAP at 300 °C. Microstructural evolution and texture development were tracked using EBSD. Analysis revealed continuous dynamic recrystallization (CDRX) as one of the grain refinement mechanism during processing. Room temperature tensile tests carried out before and after six passes, shows significant increase in strength with acceptable levels of ductility. The yield strength was increased from 308 to 558 MPa and ultimate tensile strength from 549 to 685 MPa. Compression tests conducted at different strain rates shows considerable increase in strength and enhanced strain rate sensitivity after processing. A distinct three-stage strain hardening was observed during compression. However the processed material displayed a loss in strain hardening ability during tensile as well as in compression tests. Detailed microhardness measurements show the evolution of hardness after subsequent passes with a reasonable level of homogeneity after the sixth pass. It is demonstrated that I-ECAP is an effective method for grain refinement in CP-Ti and subsequently improving its mechanical properties

Mechanical properties of AZ31B magnesium alloy were modified in this work by various processing routes of incremental equal channel angular pressing (I-ECAP) followed by heat treatment. Possible strategies for improving ductility and strength of the alloy were investigated. Processing by routes A and BC showed that texture plays predominant role in controlling mechanical properties at room temperature. Four passes of I-ECAP by route C followed by annealing enhanced ductility up to 0.35 of true strain. It was found that tensile twinning was important in accommodating strain during tensile testing, which resulted in a very good hardening behaviour. The yield strength was improved to 300 MPa by refining grain size to 0.8 µm in I-ECAP at 150 °C. The obtained structure and properties were shown to be stable up to 150 °C. True strain at fracture was increased to 0.2 after annealing at 150 °C without lowering strength

Incremental equal channel angular pressing (I‐ECAP) is used in this work to produce ultrafine‐grained (UFG) pure iron, aluminum alloy 5083, commercial purity titanium (grade 4), and magnesium alloy AZ31B. Pure iron is processed at room temperature, aluminum alloy at 200 °C, titanium at 320 °C, and magnesium alloy at 150 °C. Strength improvement, attributed to the grain refinement below 1 μm, is reported for all processed materials. The yield strength increase is the most apparent in pure iron, reaching almost 500 MPa after one pass of I‐ECAP, comparing to 180 MPa in the as‐forged conditions. UFG titanium, aluminum, and magnesium alloys obtained in this study reached yield stress of 800, 350, and 300 MPa, respectively, in each case exhibiting the yield strength increase by at least 30%, comparing to the alloys processed by conventional metal forming operations such as forging and rolling.

Influence of the Sr and Mg alloyIng addItIonS on the bondIng between MatrIx and reInforcIng partIcleS In the alSi7Mg/Sic-cg hybrId coMpoSIteThe aim of the work was to perform adequate selection of the phase composition of the composite designated for permanent -mould casting air compressor pistons. The hybrid composites based on AlSi7Mg matrix alloy reinforced with mixture of silicon carbide (SiC) and glassy carbon (Cg) particles were fabricated by the stir casting method. It has been shown that the proper selection of chemical composition of matrix alloy and its modification by used magnesium and strontium additions gives possibility to obtain both the advantageous casting properties of composite suspensions as well as good bonding between particles reinforcements and matrix.

This paper presents an investigation on the evolution of microstructure and deformation characteristics of commercial purity Titanium (CP-Ti) during incremental equal channel angular pressing (I-ECAP). CP-Ti grade 2 was subjected to six passes at 300 °C following route BC, using a die with channel angle of 120°. Electron backscatter diffraction (EBSD) technique was used to characterize the microstructure after first, second, fourth and sixth pass, in the flow and transverse plane of the samples. Texture development through subsequent processing was also investigated using pole figures in both planes. Following first pass, the grain boundary maps across both flow and transverse plane showed a high degree of heterogeneity in grain morphology with the presence of elongated and fine grains. Also, misorientation peaks associated with {10-12} tensile twins and a small fraction of {11-22} compressive twins were observed in the microstructure. After second pass, microstructure was further refined and the twinning activity was greatly reduced with no noticeable activity after the fourth pass. Remarkable grain refinement was achieved after sixth pass with majority of grains in the ultrafine grain (UFG) range and with a relatively homogenous microstructure. Continuous dynamic recrystallization (CDRX) has been observed during subsequent I-ECAP processing. It was seen that twinning alongside CDRX acted as a dominant grain refinement mechanism during the initial passes of I-ECAP process beyond which slip was dominant deformation behaviour