A magnesium-based alloy with theoretical strength

• 来源期刊: 科学通报（英文版）
• 年，卷（期）: 2017,（14）
• 页码范围: 978-979
• 页数: 2页
• 语种: 英文

摘要

One of the major tasks of material scientists and engineers is to increase the strength of engineering materials.Particularly under the current pressure of carbon emission,automotive and aerospace industries not only require materials with high strength,but also need lightweight in order to improve the fuel efficiency through weight reduction.Thus,light alloys,aluminium alloys and magnesium alloys in particular,have attracted increasing interest to these industry sectors.To date,the highest yield strength reported for aluminium alloys is up to 1,000 MPa after severe plastic deformation [1] and it is 440 MPa for magnesium alloys after equal channel angular pressing (ECAP) process [2].These values are far below the theoretical strength of the metals,which is generally approximated to E/10 [3],where E is the Young's modulus.The much lower strength of engineering alloys is attributed to the defects,dislocations in particular,in the alloys.Because defects-containing alloys are thermodynamically stable due to higher entropy,it is extremely difficult to completely remove them.Hence,over the past century,almost all alloys are strengthened by introducing more defects,such as dislocations,various types of interfaces,hard particles and solutes,in order to hinder the movement of dislocations.