Development of microstructure control technology and high-peformance Mg alloy sheets

2020 Fiscal Year Final Research Report

• Project/Area Number: 19K15321
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 26050:Material processing and microstructure control-related
• Research Institution: Nagaoka University of Technology
• Principal Investigator: Nakata Taiki 長岡技術科学大学, 産学融合トップランナー養成センター, 産学融合特任講師 (80800573)
• Project Period (FY): 2019-04-01 – 2021-03-31
• Keywords: マグネシウム合金 / 圧延加工 / 時効析出 / 室温成形性 / 引張特性 / 電子線後方散乱回折 / 結晶塑性シミュレーション / 電子顕微鏡

Outline of Final Research Achievements

In this study, we have successfully developed a precipitation-hardenable Mg-Zn based alloy sheet with excellent strength-ductility balance and good room-temperature stretch formability. The newly developed alloy sheet shows good Index Erichsen value over 7mm, and the 0.2% proof stress was improved to 228MPa by a peak-aging treatment. Moreover, the peak-aged alloy sheet could keep moderate elongation to failure of about 20% and then it was found that the new sheet exhibits better tensile properties than those of previously designed room-temperature formable Mg alloy sheets. Besides, we have tried to elucidate the recrystallization mechanism via electron backscattered diffraction technique, and it could be understood that twinning-induced static recrystallization plays an important role for the texture formation in Mg alloys.

Free Research Field

材料加工・組織制御工学

Academic Significance and Societal Importance of the Research Achievements

一般的なマグネシウム合金は、強度や延性、室温成形性の同時改善が困難であることから、安価な輸送機器構造部材としての実用化は困難と考えられていたが、本研究の結果、時効析出を利用することで、マグネシウム合金でも優れた引張特性と成形性の同時付与が可能であることを見出した。また、双晶によってマグネシウム合金の集合組織を制御できることも実証した。これは、マグネシウム合金押出材や鍛造材の組織制御にも有効であり、マグネシウム展伸材の高性能化を目指した基盤技術になると考えられる。