Pacific National University, Khabarovsk, Russia

N. A. Slavinskaya, Lecturer of Higher School of Industrial Engineering, Polytechnic Institute, e-mail: 010763@pnu.edu.ru
H. Ri, Professor of Higher School of Industrial Engineering, Polytechnic Institute, Doctor of Technical Sciences, e-mail: 000396@pnu.edu.ru
E. Н. Ri, Head of Higher School of Industrial Engineering, Polytechnic Institute, Doctor of Technical Sciences, Professor, e-mail: erikri999@mail.ru
A. S. Zhivetev, Associate Professor of Higher School of Industrial Engineering, Polytechnic Institute, Candidate of Technical Sciences, e-mail: 007881@pnu.edu.ru

The paper presents the studies on the effect of quenching temperature during artificial aging (at 155 ^oС and holding time of 4 h) on the structure formation, character of the distribution of elements in structural constituents and their microhardness, hardness of alloy AM4.5Cd modified with cerium (0.2 % (wt.)). The authors have determined that higher quenching temperature and subsequent artificial aging contributed to coarsening of structural constituents: α-solid solution, intermetallic phases and eutectics. Electron microscopy and X-ray microanalysis methods were applied to identify structures at various quenching temperatures. Content of copper and manganese varies unevenly. The analysis showed two types of α-solid solutions (α₁ and α₂) with different chemical compositions. Content of Cu and Mn, % (at.): 2.0 Cu and 0.25 Mn in α₁-solid solution shows no changes up to a quenching temperature of 585 ^oС, solubility of alloying elements in α₂-solid solution varies according to the extremal dependence, demonstrating maximum values of copper (3.5 % (at.)) and manganese (3.5 % (at.)) at a quenching temperature of 565 ^oС. Every value of quenching temperature (535, 545, 565, 585, and 605 ^oС, respectively) was attributed to intermetallic phases of certain stoichiometry, mostly aluminides of titanium Al_xTi_yiCe_zCd_vCu_w and copper Al_xCu_yMn_zCd_v. The authors identified relations between compositions of α-solid solutions, intermetallic compounds and their microhardness, and quenching temperature. Thus, an increase in quenching temperature to 545 oС contributes to an increase in hardness of alloy AM4.5Cd + 0.2 % (wt.) Ce to 104 HB, and a sharp decrease to 60 HB at 605 ^oС.

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