Recrystallization Behavior of CoCrCuFeNi High-Entropy Alloy
Recrystallization Behavior of CoCrCuFeNi High-Entropy Alloy
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DOI：
10.1007/s11661-014-2594-5
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发表时间：
2015-04-01
影响因子：
2.8
通讯作者：
Tsuji, Nobuhiro
中科院分区：
文献类型：
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作者：
Park, Nokeun;Watanabe, Ikuto;Tsuji, Nobuhiro
研究了冷轧CoCrCuFeNi高熵合金的再结晶行为。铸态样品中两种不同化学成分和晶格常数的面心立方相具有不同的化学成分：一相为贫铜基质，另一相为富铜第二相。即使在137K(1100摄氏度)的热处理后，第二相仍然存在，富铜的第二相中铜的含量更高。计算的铸态和热处理样品中贫铜相和富铜相的混合热解释了热处理过程中铜的分配降低了这两个相的混合热。在923K、973K和1073K(650A℃、700A℃和800A℃)下进行90%冷轧和热处理的样品中，再结晶随退火温度的升高而进行，可获得晶粒尺寸在1微米左右的超细再结晶组织。随着再结晶比例的增加，显微硬度呈下降趋势，但部分再结晶试件的显微硬度远高于原始试件和冷轧试件之间简单的混合规则所预期的硬度值。从CoCrCuFeNi合金中的超细晶粒尺寸、扩散迟缓以及CoCrCuFeNi合金中的两相组织等方面分析了合金硬度偏高的原因。(C)2014年矿物、金属和材料学会和ASM国际
We investigated the recrystallization behavior of a cold-rolled CoCrCuFeNi high-entropy alloy (HEA). Two different face-centered cubic phases having different chemical compositions and lattice constants in the as-cast specimen have different chemical compositions: One phase was the Cu-lean matrix and the other was the Cu-rich second phase. The second phase remained even after a heat treatment at 1373 K (1100 A degrees C) and Cu enriched more in the Cu-rich second phase. The calculated mixing enthalpies of both Cu-lean and Cu-rich phases in the as-cast and heat-treated specimens explained that Cu partitioning during the heat treatment decreased the mixing enthalpy in both phases. In the specimens 90 pct cold rolled and annealed at 923 K, 973 K, and 1073 K (650 A degrees C, 700 A degrees C, and 800 A degrees C), recrystallization proceeded with increasing the annealing temperature, and ultrafine recrystallized grains with grain sizes around 1 mu m could be obtained. The microhardness tended to decrease with increasing the fraction recrystallized, but it was found that the microhardness values of partially recrystallized specimens were much higher than those expected by a simple rule of mixture between the initial and cold-rolled specimens. The reason for the higher hardness was discussed based on the ultrafine grain size, sluggish diffusion expected in HEAs, and two-phase structure in the CoCrCuFeNi alloy. (C) The Minerals, Metals & Materials Society and ASM International 2014