Thermal stability and mechanical properties of nanocrystalline Fe–Ni–Zr alloys prepared by mechanical alloying
Thermal stability and mechanical properties of nanocrystalline Fe–Ni–Zr alloys prepared by mechanical alloying
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DOI：
10.1007/s10853-013-7652-7
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发表时间：
2013-08
影响因子：
4.5
通讯作者：
H. Kotan;K. Darling;M. Saber;R. Scattergood;C. Koch
中科院分区：
文献类型：
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作者：
H. Kotan;K. Darling;M. Saber;R. Scattergood;C. Koch
Zr添加量高达4at.%的纳米结构Fe 100 −x− yNixZr γ合金的热稳定性被查这扩展了我们以前对Fe-Ni基合金的结果，该结果被限制为1 at. Zr添加。重点放在理解的组成和微观结构的演变对晶粒生长和机械性能退火后的温度接近和高于bcc到fcc的转变。结果表明，由于bcc到fcc的转变（发生在700 °C），异常生长的fcc晶粒的突然出现，可能会失去微观结构的稳定性。然而，它被确定，晶粒生长可以在较高的温度下抑制动力学高Zr含量的合金由于金属间化合物的沉淀。最终，在更高的温度下，无论成分如何，纳米结晶性的保留都丧失了，留下了填充有纳米级金属间沉淀物的细微米晶粒。尽管晶粒尺寸的增加，原位形成的沉淀物被发现诱导奥罗万硬化效应媲美预测的最小晶粒尺寸的霍尔-佩奇硬化。报道了这些合金从晶粒尺寸强化到沉淀强化的转变。大的晶粒尺寸和高的沉淀硬化导致材料表现出高强度和显著的塑性应变能力。
The thermal stability of nanostructured Fe100−x−yNixZryalloys with Zr additions up to 4 at.% was investigated. This expands upon our previous results for Fe–Ni base alloys that were limited to 1 at.% Zr addition. Emphasis was placed on understanding the effects of composition and microstructural evolution on grain growth and mechanical properties after annealing at temperatures near and above the bcc-to-fcc transformation. Results reveal that microstructural stability can be lost due to the bcc-to-fcc transformation (occurring at 700 °C) by the sudden appearance of abnormally grown fcc grains. However, it was determined that grain growth can be suppressed kinetically at higher temperatures for high Zr content alloys due to the precipitation of intermetallic compounds. Eventually, at higher temperatures and regardless of composition, the retention of nanocrystallinity was lost, leaving behind fine micron grains filled with nanoscale intermetallic precipitates. Despite the increase in grain size, the in situ formed precipitates were found to induce an Orowan hardening effect rivaling that predicted by Hall–Petch hardening for the smallest grain sizes. The transition from grain size strengthening to precipitation strengthening is reported for these alloys. The large grain size and high precipitation hardening result in a material that exhibits high strength and significant plastic straining capacity.