Metal Science and Heat Treatment

doi: 10.1007/s11041-019-00339-9pmid: N/A

Bogdanova, T.; Merkulova, G.; Gil’manshina, T.

doi: 10.1007/s11041-019-00318-0pmid: N/A

The effect of manganese and iron on the structure of AK12 silumin is studied by microscopic x-ray diffraction and spectrum analyses. Experimental alloys with Fe : Mn = 1 : 0, 1 : 0.5, 1 : 0.7 and 1 : 1 are investigated. Quantitative analysis of the microstructure is performed. The hub zone is studied for two models of car wheels. Recommendations for alloying AK12 silumin with manganese and iron for raising its mechanical characteristics are given.

Medvedeva, S.; Zolotarevskii, V.; Yakovtseva, O.

doi: 10.1007/s11041-019-00322-4pmid: N/A

The effect of heat treatment modes of copper silumins with 4% Cu and different concentrations of silicon and magnesium crystallized in sand molds on their microstructure and mechanical properties is studied. It is shown that the level of the strength and ductility parameters of the copper silumins after the treatment depends primarily on the degree of dissolution of phase CuAl2 and that the concentration of magnesium in copper silumins with 4% Si + 4% Cu should not exceed 0.1 – 0.12%, which is sufficient for raising the strength characteristics without noticeable degradation of the ductility. The optimum mode for aging of alloy Al – 4% Si – 3.9% Cu – 0.13% Mg (160°C, 8 h), which provides σ0.2 = 330 MPa, σr = 400 MPa and δ = 2%, is determined by computation.

Popova, E.; Kotenkov, P.; Shubin, A.

doi: 10.1007/s11041-019-00320-6pmid: N/A

The conditions of formation of metastable Zr or Ti aluminides with Y under crystallization of superheated melts of the Al – Zr – Y and Al – Ti – Y systems with hypoeutectic and hypereutectic compositions with respect to yttrium are studied. Complex Al3(Zr0.67Y0.33) and Al n (Ti0.67Y0.33) aluminides with cubic lattices are shown to form due to crystallization of the Al – Zr – Y and Al – Ti – Y melts hypereutectic with respect to yttrium after superheating by 300°C above the liquidus temperatures.

Churyumov, A.; Mohamed, I.

doi: 10.1007/s11041-019-00321-5pmid: N/A

Composite materials based on aluminum alloy Al – 9% Si – 0.6% Mg are obtained by stirring ceramic particles of silicon carbide into the melt and subsequent pressure crystallization. The effect of the content of ceramic particles on the properties of the composites is studied. It is shown that the joint use of two operations, i.e., stirring-in of particles and pressure crystallization, lowers the porosity and improves the distribution of particles in the structure. The composite materials obtained possess high mechanical properties and promise successful application in the automotive and aerospace industries.

Chen, Fengyuan; Tang, Binbin

doi: 10.1007/s11041-019-00319-zpmid: N/A

Aluminum alloy 6061 is studied after an ultrasonic treatment conducted at different vibration amplitudes in the casting process. The alloy is subjected to a diffraction analysis with processing of the spectra by the Rietveld method using the MAUD (Materials Analysis Using Diffraction) software. The texture parameters, the rms strain, the lattice parameter, and the crystallite size are determined by the Rietveld technique. It is shown that the porosity of the alloy deceases considerably after the ultrasonic treatment, which also affects positively the texture of the alloy.

Grabovetskaya, G.; Ratochka, I.; Mishin, I.; Lykova, O.; Zabudchenko, O.

doi: 10.1007/s11041-019-00323-3pmid: N/A

The effect of pre-recrystallization annealing on the evolution of the structural and phase state and the deformation and fracture behavior of ultrafine-grained titanium alloy VT16 obtained by pressing with change of the deformation axis and gradual lowering of the temperature within 1023 – 723 K is studied. It is shown that the process of pre-recrystallization annealing is accompanied by retrogression of the strained structure, which lowers the strength characteristics, and by a β → α phase transformation and redistribution of the alloying elements, which keep the strength properties at a high level.

Muratov, V.; Morozova, E.

doi: 10.1007/s11041-019-00338-wpmid: N/A

The effect of laser surface alloying with nickel and manganese on the structure, phase composition, microhardness, and fretting resistance of the surface of titanium is studied. Treatment modes improving the structure and properties of the surface layers of titanium are determined.

Povarova, K.; Bazyleva, O.; Drozdov, A.; Morozov, A.; Arginbaeva, E.; Antonova, A.

doi: 10.1007/s11041-019-00324-2pmid: N/A

The nature of stability of dendritic microsegregation of rhenium in single crystals of intermetallic (γ′ + γ) alloys based on γ′-Ni3Al is determined under a high-temperature heat treatment and under creep and endurance tests. It is assumed that steady dendritic microsegregation of rhenium is a factor determining the high high-temperature strength of rhenium-containing (γ′ + γ) alloys based on γ′-Ni3Al.

Zhao, Kai; Jiang, Yueyue

doi: 10.1007/s11041-019-00325-1pmid: N/A

Comparative analysis of the microstructure and microhardness of austenitic-ferritic high-strength iron after heat treatments involving single-stage and double-stage quenching from the austenitic or intercritical temperature ranges and tempering is performed with the use of dilatometry, measurement of microhardness, and optical and scanning electron microscopy. The possibility of the use of two-stage austenitization for heat treatment of austenitic-ferritic cast irons for raising their properties is studied.