Metal Science and Heat Treatment

Pozdnyakov, A.; Barkov, R.; Yakovtseva, O.; Levchenko, V.; Prosviryakov, A.; Zolotorevskii, V.

doi: 10.1007/s11041-019-00439-6pmid: N/A

The evolution of the structure and mechanical properties of sheets from alloy Al – 4.7% Mg – 0.32% Mn – 0.21% Sc – 0.09% Zr during warm rolling and subsequent annealing is studied. It is shown that extended fibers with a thickness of 50 – 100 nm form inside the deformed grains in the rolling process. Post-rolling annealing of the sheets at 150 and 200°C results in substantial lowering of the elongation after a hold for 3 h; then the ductility recovers after a hold for 5 h. The lowering of the ductility is associated with precipitation of a fine β -phase over grain boundaries during the annealing. The phase grows and its volume fraction decreases when the annealing time is prolonged. The possibility of formation of high-level mechanical properties after warm rolling and subsequent annealing is shown.

Farber, V.; Polukhina, O.; Vichuzhanin, D.; Khotinov, V.; Smirnov, S.

doi: 10.1007/s11041-019-00437-8pmid: N/A

Regular features of Luders strain due to appearance and propagation of one Chernov–Luders band (CLB) in superfine-grained steel 08G2B are investigated. Active, relaxation and peripheral zones are distinguished in the source of strain uniting the CLB nucleus; go-ahead-activated flow channels are defined. The functions of the zones are considered. Growth in the dislocation density and in the energy spent in the zones upon motion of the CLB front is evaluated. Mechanisms of appearance of new slip bands in the CLB and of unlocking of dislocations are analyzed.

Glotka, A.; Moroz, A.

doi: 10.1007/s11041-019-00456-5pmid: N/A

The effects of carbides and nonmetallic inclusions on formation of fatigue microcracks in steels for high-load bearings are determined. The running time is shown to affect the growth of parameter N c/N t for all the steels studied. The size of the carbides is shown to affect the degree of propagation of fatigue microcracks; the fraction of carbides with fatigue microcracks grows with their size. The results obtained are helpful in choosing the direction of optimization of the structure of carbide phases in bearing steels.

Rokhlin, L.; Dobatkina, T.; Luk’yanova, E.; Tarytina, I.; Temralieva, D.

doi: 10.1007/s11041-019-00443-wpmid: N/A

The kinetics of decomposition of supersaturated magnesium solid solution and of the accompanying hardening of the latter at 200°C in cast alloy IMV7-1 of the Mg – Y – Gd – Zr system alloyed with two rare-earth metals, i.e., holmium and ytterbium, is studied. Holmium and ytterbium are introduced into IMV7-1 by substituting two other rare-earth metals, i.e., yttrium and gadolinium. It is shown that the presence of holmium and ytterbium instead of yttrium and gadolinium does not change the decomposition behavior of the supersaturated solid solution but decelerates this process and lowers the effect of age hardening.

doi: 10.1007/s11041-019-00446-7pmid: N/A

Kara, İ.; Ahlatci, H.; Türen, Y.; Sun, Y.

doi: 10.1007/s11041-019-00442-xpmid: N/A

The effect of lanthanum additions (0.2 – 1.0%) on the microstructure and mechanical properties of magnesium alloy AZ31 is studied after hot rolling with deformation of 15 and 30%. The microstructure is analyzed by the methods of x-ray diffractometry, optical microscopy and scanning electron microscopy. The mean values of the ultimate strength, elongation and contraction are determined in tensile tests.

Molchanova, N.; Iksanov, M.; Leonov, V.

doi: 10.1007/s11041-019-00450-xpmid: N/A

Results of a study of the effect of a modifier (boron carbide) on the microstructure and mechanical properties of a castable titanium pseudo-α-alloy are presented.

Çömez, Nilay; Durmuş, Hülya

doi: 10.1007/s11041-019-00440-zpmid: N/A

The effect of the parameters of welding conducted by the method of cold metal transfer on the geometry of the welding pool, the ultimate tensile strength, and the corrosion rate of welded joints of sheets from aluminum alloy AA6061 is studied. The influence of the current, voltage, and heat input rate during welding on the properties of the welded joints is analyzed. The welding parameters providing maximum ultimate strength and high corrosion resistance of welded joints of alloy AA6061 are determined.