【摘要】 利用CALPHAD方法预测了Co基粘结层合金元素对相组成的影响,计算结果表明:Al对β′和γ相的析出量影响显著,Cr对σ相的析出量影响显著,从而确定了Al和Cr元素合适的成分范围分别于13%和22%附近。在此基础上计算了设计成分合金的相组成随温度的变化规律,结果表明:合金于1208℃开始从基体β′相中析出γ相,974℃时,γ含量达到最高,随后将析出脆性的σ相。依据此相转变规律建议给出了合金的热处理工艺,1300℃固溶,结合1000℃时效处理。采用真空感应熔炼制备合金样品,铸态合金经上述热处理后得到β′+γ的两相组织,合金元素的偏析明显改善,非晶组织基本消除,得到较为理想的热障涂层粘结层用Co基合金靶材。更多还原

【Abstract】 The effects of alloying elements on phase equilibria in Co-based bond coating alloys were predicted by CALPHAD method. The results show that Al significantly influences the precipitation amounts of β′ and γ, and Cr has a definite effect on the precipitation of σ. The appropriate contents of Al and Cr elements are determined to be around 13% and 22%, respectively. The results of calculated phase formations and phase change as a function of temperature were extensively discussed, which indicate that γ begins to precipitate from the matrix β′ at 1208℃ and reaches the highest content at 974℃, and then the σ precipitates. According to the phase transformation, the heat treatment process of the alloy was formulated, i.e. dissolving at 1300℃ and aging at 1000℃. The alloy samples were prepared by vacuum induction melting. Segregation and the amorphous structure in as-cast alloys are eliminated after the above heat treatment, and the two-phase structure, β′+ γ, of the commercial target is obtained.更多还原