摘要
为了研究退火温度对AlCoCrFeMnTi高熵合金的物相结构、显微组织及硬度的影响,分别采用X射线衍射仪、光学显微镜、扫描电镜和显微硬度计对不同退火温度下AlCoCrFeMnTi合金进行了测试。结果表明:铸态AlCoCrFeMnTi高熵合金物相结构是由bcc主相和fcc相双相组成,且其各相衍射峰普遍较宽,这是由于原子半径差较大和冷却速度快引起的晶格畸变所致。600℃退火后,合金中形成了新的hcp相,当退火温度为800℃和1000℃时,合金衍射峰的峰形并未再发生显著变化。铸态和退火后的AlCoCrFeMnTi合金均为典型的树枝晶结构,1000℃退火后的扫描电镜照片中发现了典型的调幅分解组织。合金硬度值在铸态最大,达到了750HV0.5,随着退火温度升高硬度逐步降低。在经过1000℃退火后,一方面由于合金中出现调幅分解组织,使得过饱和的原子大量析出,降低了晶格畸变程度,导致硬度下降;另一方面,由于退火温度的升高,加速了原子的扩散能力,降低了合金内部的内应力,此时合金硬度下降到604.9HV0.5。
Effect of annealing temperature on the phase constitution,microstructure and hardness of AlCoCrFeMnTi high entropy alloy were tested by means of XRD,OM,SEM and microhardness tester. The results show that the phase structure of as-cast AlCoCrFeMnTi high entropy alloy is composed of bcc main phase and fcc phase,and the diffraction peaks of each phase are generally wider,which is due to lattice distortion caused by large difference of alloy atomic radius and fast cooling rate. The microstructure of AlCoCrFeMnTi alloy is composed of dendrite and intergranular,and is the typical dendrite structure. A new hcp phase is formed in this alloy when annealed at 600 ℃ .The peak shape of the diffraction peak does not change significantly when annealed at 800 ℃ and 1000 ℃ . The microstructure of the as-cast AlCoCrFeMnTi alloy and the annealed alloy are all typical dendritic structure. Typical amplitude-modulated decomposition structure is revealed by scanning electron micrograph after annealing at 1000 ℃ . The hardness of the as-cast alloy is the largest( 750 HV0. 5) and decreases gradually with the increase of annealing temperature. After annealing at 1000 ℃,the alloy is deformed due to the amplitudedecomposing structure in the alloy. Supersaturated atoms are shifted in a large amount,which reduces the degree of lattice distortion and leads to a decrease of hardness. On the other hand,due to the increase of the annealing temperature,the atomic diffusion capacity is accelerated and the internal stress of the alloy is lowered. At this time,the hardness of the alloy drops to 604. 9 HV0. 5.
作者
王志新
周家臣
马明星
卢金斌
朱达川
张德良
Wang Zhixin;Zhou Jiachen;Ma Mingxing;Lu Jinbin;Zhu Dachuan;Zhang Deliang(School of Materials&Chemical Engineering,Zhongyuan University of Technology,Zhengzhou Henan 450007,China;School of Mechanical Engineering,Suzhou University of Science and Technology,Suzhou Jiangsu 215009,China;College of Materials Science and Engineering,Sichuan University,Chengdu Sichuan 610065,China;School of Materials Science and Engineering,Northeastern University,Shenyang Liaoning 110819,China)
出处
《金属热处理》
CAS
CSCD
北大核心
2020年第4期144-148,共5页
Heat Treatment of Metals
基金
国家自然科学基金(51271115)
河南省重点科技攻关项目(142102210084)
郑州市中小企业创新基金(122PCXJJ806)。
关键词
高熵合金
退火
微观组织
硬度
high entropy alloy
annealing
microstructure
hardness
