文章信息/Info

Title:

Heterogeneous Microstructure Design and Property Optimization of Titanium Alloys Assisted by Phase Field Simulation

文章編號:

1674-3962(2022)07-0497-11

作者:

郝夢園1; 2; 李沛3; 王棟1; 2

(1. 西安交通大學前沿科學技術研究院，陜西 西安 710049) (2. 西安交通大學 金屬材料強度國家重點實驗室，陜西 西安 710049) (3. 西安熱工研究院有限公司 清潔低碳熱力發電系統集成及運維國家工程研究中心，陜西 西安 710032)

Author(s):

HAO Mengyuan1; 2;  Li Pei3;  WANG Dong1; 2

(1. Frontier Institute of Science and Technology, Xi’an Jiaotong University, Xi’an 710049, China) (2. State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an 710049, China) (3. Thermal Power Research Institute Co. Ltd., National Engineering Research Center of Integration and Maintenance of Clean and Low-Carbon Thermal Power Generation System, NERC of TPGS, Xi’an 710032, China)

關鍵詞:

鈦合金; 相場模擬; 雙步時效; 連續冷卻; 多尺度微觀組織

Keywords:

titanium alloy;  phase field simulation;  two-step aging;  continuous cooling;  heterogeneous microstructure

分類號:

TG146.23

DOI:

10.7502/j.issn.1674-3962.202112021

文獻標志碼:

A

摘要:

在科學研究和工程應用中，同時提高結構材料的強度和塑性仍然面臨著巨大的挑戰。根據相場模擬微觀組織指導模型材料設計的思路，提出了通過激活不同的形核機制設計合金多尺度微觀組織的新方法，進而克服結構材料強度和塑性不匹配效應。以雙相鈦合金為例，將真實熱力學數據庫與相場模型相耦合，探索了不同熱處理工藝對合金微觀組織的影響規律，提出了選擇合適溫度和時間的雙步時效和調控冷速的熱處理方案。基于模擬結果，實驗時在Ti1023合金中分別提出了650 ℃/10 min+550 ℃/180 min雙步時效工藝、0.3125 ℃/min連續冷卻的熱處理工藝，并產生了多尺度析出組織。進一步的力學性能測試表明，相較于傳統的均勻組織，新獲得的多尺度微觀組織具有更好的強度與塑性匹配性能。所提出的基于相變理論的熱處理工藝通過調控多尺度析出組織來優化性能的思路，為其它結構材料的性能提高提供了方向。

Abstract:

Improving the strength and ductility of structural materials simultaneously is still facing great challenges in scientific research and engineering applications. With the idea of guiding the design of model materials by phase field simulating microstructure, this paper proposes new methods for designing heterogeneous microstructure by activating different nucleation mechanisms to overcome the trade-off strength and ductility in structural material. Taking dual-phase titanium alloy as an example, this paper explores the influence of different heat treatment processes on the microstructure of the alloy by coupling the real thermodynamic database and the phase field model, and proposes a two-step aging that selects an appropriate aging temperature and time and a heat treatment scheme that regulates the cooling rate. Based on the simulation results, in the experiment, two-step aging (650 ℃/10 min+550 ℃/180 min) and continuous cooling (0.3125 ℃/min) were proposed in the Ti1023 alloy, and multi-scale heterogeneous microstructures were produced in the β titanium alloy. Further mechanical properties tests showed that the newly obtained heterogeneous microstructures have better strength-ductility matching properties compared to the conventional homogeneous microstructure. The idea of optimizing the properties by modulating the multiscale precipitation microstructure through the heat treatment process based on the phase transition theory proposed in our work provides a direction for the performance improvement of other structural materials.