Metal Science and Heat Treatment

doi: 10.1007/s11041-022-00752-7pmid: N/A

Zorina, M. A.; Karabanalov, M. S.; Loginov, Yu. N.; Lobanov, M. L.

doi: 10.1007/s11041-022-00753-6pmid: N/A

Special features of deformation and recrystallization textures in a copper capillary tube produced by drawing and subjected to annealing in a vacuum furnace at 500°C for 5.5 h are studied. The textures of the specimens are analyzed by the EBSD technique. It is shown that both textures are homogeneous over the entire cross section of the tube and match on the whole the deformation and recrystallization textures of cold-rolled copper sheets. Grains with orientations located at the scattering edges of the deformation texture grow under the recrystallization and deviate from the accurate deformation orientations by turning about their axes by 50 – 70° going close to <110>. A hypothesis explaining the recrystallization texture by formation of nuclei in the regions of deformation twins is suggested.

Novikov, V. Yu.

doi: 10.1007/s11041-022-00754-5pmid: N/A

The causes of rapid growth of coarse grains under secondary recrystallization are analyzed. According to the available experimental data the rapidly migrating boundaries of such grains are retarded by disperse particles less than by other particles. Numerical simulation shows that such behavior of coarse grains is responsible for formation of a microstructure typical for secondary recrystallization. The results obtained are important for creation and advancement of the technology of metallic and ceramic materials, the properties of which are affected by appearance and development of secondary recrystallization.

Darvishi, Alireza; Daneshmayeh, Aria; Salehi, Alihosein; Ahmadi, Mahdi

doi: 10.1007/s11041-022-00755-4pmid: N/A

The effects of single and double austenitization at 900, 590, 1000 and 1050°C on the microstructure and hardness of quenched and tempered steel 1.4% C – 11.7% Cr (FMU-11) are studied. The metallographic analysis is performed by optical and electron scanning microscopy. The microhardness is measured at low (10 kg) and high (150 kg) loads. The volume content of retained austenite and primary and secondary carbides in the structure is determined. It is shown that double austenitization reduces the size of the carbides and raises the content of retained austenite as compared to single austenitization. Elevation of the austenitization temperature results in lowering of the hardness of the steel.

Popov, A. A.; Popov, N. A.; Lugovaya, K. I.; Popova, E. N.; Narygina, I. V.

doi: 10.1007/s11041-022-00756-3pmid: N/A

Analysis of lattice mismatch of the α- and α2-phases is performed as a function of the original structure and solid solution alloying for titanium pseudo-α-alloys with elevated content of aluminum. The structure of the alloys is studied by scanning and transmission electron microscopy and x-ray diffraction analysis. It is shown that alloying with tin and zirconium lowers the lattice mismatch of the phases, especially in the case of formation of an α + α2 structure by a spinodal mechanism. The thermal stability of the forming structures is discussed.

Qu, Yauntao; Luo, Zhiting; Dong, Xin; Zhou, Yanan; Sun, Qi; Wu, Miaomiao; Li, Ning; Yan, Jiazhen; Zhang, Biao; Li, Rui; Xu, Sheng

doi: 10.1007/s11041-022-00760-7pmid: N/A

The effect of annealing at 700, 800, 900 and 1000°C on the microstructure and mechanical properties of alloy Ti – 6% Al – 4% V obtained by selective laser melting is studied. The ultimate tensile strength, the yield strength, the elongation, and the hardness of samples of the titanium alloy are determined in the initial condition and after annealing. X-ray diffraction and phase analyses are performed. The changes in the structure of the alloy during annealing at different temperatures are analyzed. It is shown that the intensity of the structural changes increases with the annealing temperature, while the microhardness and the strength characteristics decrease, and the ductility grows.

Kondrat’ev, S. Yu.; Belikova, Yu. A.; Fuks, M. D.; Frolov, M. A.; Petrov, S. N.

doi: 10.1007/s11041-022-00759-0pmid: N/A

The microstructure, the phase composition and the mechanical properties at 20°C and 870°C of a tubular welded joint from alloy HP40NbTi based on the Fe – 25% Cr – 35% Ni system are determined. The mechanism of fracture of the joint under short-term and long-term loading is studied. The role of the G-phase in nucleation and propagation of cracks in the structure of the alloy is revealed. An intermetallic G-phase is shown to form in the heat-affected zone under welding. It is shown that the G-phase lowers the long-term strength of the welded joint of alloy HP40NbTi as compared to the matrix metal.

Najafizadeh, Mojtaba; Ghasempour-Mouziraji, Mehran

doi: 10.1007/s11041-022-00757-2pmid: N/A

The process of formation of surface layer on steel AISI D2 pack siliconized at 650, 800 and 950°C for 2, 3, and 4 h using a powder mixture (in wt.%) of 0.5, 0.75, 1.0 NH4Cl + 12 Si, the remainder Al2O3 is studied. The siliconized layer is analyzed by x-ray diffractometry and electron microscopy, and its microhardness is measured. It is shown that the thickness and the microhardness of the coating increase with the temperature and the treatment time and with the content of the halide activator. The response surface methodology based on the Box–Behnken method is used to optimize the siliconizing process for steel AISI D2.

Shoba, M. Kantha; Mohan, K. Malar; Raj, P. Praveen

doi: 10.1007/s11041-022-00758-1pmid: N/A

The microstructure, hardness and wear resistance of gray cast iron with detonation-sprayed Cr3C2 and Ni – Cr coatings are studied. It is shown that the Cr3C2 coating has stronger adhesion to the gray cast iron substrate and provides higher hardness and wear resistance than the Ni – Cr coating.

Mertgenç, Ersan; Karabas, Muhammet; Kayali, Yusuf

doi: 10.1007/s11041-022-00761-6pmid: N/A

The effect of the size of initial particles of WC – 12% Co powder on the microstructure and mechanical properties of coatings plasma sprayed onto a substrate from steel Nitronic 50 is studied. The microstructure of the coatings is investigated by scanning electron microscopy and x-ray diffraction. The microhardness and the wear resistance are determined. It is shown that the coatings deposited from the fine powder have greater thickness and almost twice lower porosity than the coatings from the coarse powder. However, the plasma sprayed coarse powder undergoes less decarburization. The coating from WC – 12% Co raises the surface hardness and wear resistance of Nitronic 50 by a factor of 6 – 7.