文章信息/Info

Title:

Study on the Annealing Behavior of Al-Mg-Mn-Sc As-cast Alloy

文章編號:

1674-3962(2021)11-0917-05

作者:

陳顯明1; 潘清林2; 范瑩瑩1

（1.肇慶學院電子與電氣工程學院，廣東 肇慶 526061) （2.中南大學材料科學與工程學院，湖南 長沙 410083）

Author(s):

CHEN Xianming1;  PAN Qinglin2; FAN Yingying1

（1. School of Electronic and Electrical Engineering, Zhaoqing University, Zhaoqing 526061, China） (2. School of Materials Science and Engineering, Central South University, Changsha 410083, China)

關鍵詞:

含鈧鋁合金; 初生/次生Al3Sc粒子; 硬度; Al-Mg-Mn-Sc合金; 粒子粗化

Keywords:

aluminum alloy with scandium;  primary/secondary Al3Sc particle;  hardness;  Al-Mg-Mn-Sc alloy; particle coarsening

分類號:

TG146

DOI:

10.7502/j.issn.1674-3962.202006001

文獻標志碼:

A

摘要:

通過水冷銅模急冷鑄造法制備了Al-5.5Mg-0.4Mn-0.25Sc合金，研究了該鑄態(tài)合金在不同退火溫度下的硬度變化，并通過金相顯微鏡和透射電鏡探討合金中Al3Sc粒子的存在形式和形成機理。結(jié)果表明：添加質(zhì)量分數(shù)為0.25%的Sc對鑄態(tài)合金晶粒組織的細化并沒有產(chǎn)生太大的貢獻，晶粒細化是由于快速凝固技術所帶來的作用，在高的冷卻速率下，合金中較難發(fā)現(xiàn)初生Al3Sc粒子的存在。退火溫度對于合金硬度有顯著影響，在低的溫度下退火時，合金硬度變化較慢，需較長時間才出現(xiàn)硬度峰值；而在較高溫度下退火時，合金硬度峰值平臺出現(xiàn)需要時間較短，但隨著退火時間延長硬度迅速下降。在所測試的退火溫度中，300 ℃下呈現(xiàn)出較好的硬度曲線，具有較高的硬度峰值平臺且能維持較長時間不下降。退火過程中合金硬度的變化與次生Al3Sc粒子的析出密切相關，退火溫度較低時次生Al3Sc粒子析出不充分、粒徑較小，對晶界、亞晶界和位錯的釘扎作用較弱；而退火溫度太高，Al3Sc粒子發(fā)生粗化，導致合金性能變差。

Abstract:

Al-5.5Mg-0.4Mn-0.25Sc(wt%) alloy was casted by water-cooled copper die. The hardness variation of the as-cast alloy annealed at different temperatures was studied. The existence modality and formation mechanism of Al3Sc particles in the alloy were investigated by metallographic microscope and transmission electron microscope. The results show that 0��25wt% Sc does not contribute much to the refinement of as-cast grain structure, and the grain refinement comes from the effect of rapid solidification technology. At high cooling rate, it is difficult to find the presence of primary Al3Sc particles in the alloy. The annealing temperature has a significant effect on the hardness of the alloy. At low annealing temperatures, the hardness of the alloy changes slowly, and it takes a long time to appear the hardness peak. At higher annealing temperatures, the peak platform appears faster, but after this peak the hardness decreases rapidly as the annealing continues. Among these temperature tests, the hardness curve of 300 ℃ is outstanding, which has a higher hardness peak platform and maintains a long time without decreasing. The change of hardness during annealing is closely related to the precipitation of secondary Al3Sc particles. When the annealing temperature is low, the precipitation of secondary Al3Sc particles is insufficient and the particle size is small, and the pinning effect on grain boundaries, sub-crystalline boundaries and dislocations is weak; while the temperature is too high, Al3Sc particles coarsen and result in poor properties.