Composition design, microstructure, and mechanical properties of novel Ti–Co–Ni–Zr complex concentrated alloys

The composition design of complex concentrated alloys originates from the composition design of amorphous alloys. To expand the composition design of alloys, herein, the compositions of novel Ti–Co–Ni–Zr complex concentrated alloys were obtained by the proportional mixing of Ti2Co intermetallics and Ni64Zr36 binary eutectic. The theory and method of this new alloy design are also discussed. The as-cast Ti28Co14Ni37.12Zr20.88, Ti30Co15Ni35.2Zr19.8, and Ti32 . Co16Ni33.3Zr18.7 alloys were composed of body-centered cubic TiNi and Ti2Ni phases. The Ti28Co14Ni37.12Zr20.88 alloy exhibited high yield strength (2 164 MPa) and compressive strength (2 539 MPa) under quasi-static compression at roomtemperature. The high strength of Ti28Co14Ni37.12Zr20.88 alloy is related to the precipitation of Ti2Ni along the grain boundary and the precipitation in the crystal. This paper validates that using the proportional mixing method of intermetallics and eutectic alloy is an effective method to design complex concentrated alloys with high strength.

Mechanical and Tibological Properties of SLM AlSi10Mg Alloy Subjected to ECAP

In this study, selectively laser melted AlSi10Mg alloy was subjected to ECAP processing for the first time. Mechanical properties of the ECAP processed samples were compared based on hardness measurement, compression and wear tests. The results showed exceptional synergy of high yield strength ~382 MPa and strain to failure of ~48% of the SLM ECAP processed sample. This sample also offered approximately ~71% higher wear resistance, than an unprocessed one. The proposed novel route expands the opportunities of both technologies to produce materials with exceptional properties.

Microstructures and Mechanical Properties of Al-Ti-Zr-Nb-Ta-Mo-V Refractory High-Entropy Alloys with Coherent B2 Nanoprecipitation

In this work, the microstructural evolution and mechanical properties of new body-centered cubic (BCC)-based Al-Ti-Zr-Nb-Ta-Mo-V refractory high-entropy alloys (RHEAs) with coherent B2 precipitation are investigated. These designed alloy ingots were solid-solutionized at 1573 K for 2 h and then aged at 873 K for 24 h, in which each treatment was followed by water quenching. It was found that there exists phase separation of BCC matrix, Ti/Zr-rich BCC1 and Nb/Ta-rich BCC2 in these alloys. Moreover, ultra-fine spherical B2 nanoparticles with a size of 3~5 nm were dispersed in BCC2 matrix. These B2 nanoparticles could be coarsened up to 25~50 nm after aging and the particle morphology also changes to a cuboidal shape due to a moderate lattice misfit (ε = 0.7~2.0%). Also, Zr5Al3 phase could coexist with the B2 phase, where the difference between them is that the Ti element is enriched in B2 phase, rather than in Zr5Al3. Among them, the solutionized Al2Ti5Zr4Nb2.5Ta2.5 RHEAs exhibit good compressive mechanical property with a high yield strength of 1240 MPa and a large plasticity, which is mainly attributed to the coherent precipitation in the BCC matrix.