Synthesis of Hybrid Nanocrystalline Alloys by Mechanical Bonding through High‐Pressure Torsion

• Published in: Advanced engineering materials Vol. 22; no. 4
• Main Authors: Han, Jae-Kyung, Herndon, Taylor, Jang, Jae-il, Langdon, Terence G., Kawasaki, Megumi
• Format: Journal Article
• Language: English
• Published: 01.04.2020
• Subjects: grain refinement; hardness; high-pressure torsion; mechanical bonding; mechanical properties
• ISSN: 1438-1656; 1527-2648
• DOI: 10.1002/adem.201901289

An overview of the mechanical bonding of dissimilar bulk engineering metals through high‐pressure torsion (HPT) processing at room temperature is described in this Review. A recently developed procedure of mechanical bonding involves the application of conventional HPT processing to alternately stacked two or more disks of dissimilar metals. A macroscale microstructural evolution involves the concept of making tribomaterials and, for some dissimilar metal combinations, microscale microstructural changes demonstrate the synthesis of metal matrix nanocomposites (MMNCs) through the nucleation of nanoscale intermetallic compounds within the nanostructured metal matrix. Further straining by HPT during mechanical bonding provides an opportunity to introduce limited amorphous phases and a bulk metastable state. The mechanically bonded nanostructured hybrid alloys exhibit an exceptionally high specific strength and an enhanced plasticity. These experimental findings suggest a potential for using mechanical bonding for simply and expeditiously fabricating a wide range of new alloy systems by HPT processing. In this Review, recent developments in innovative metal bonding of a wide variety of two or more dissimilar metals using a nanostructuring technique of high‐pressure torsion at room temperature are overviewed. The produced heterostructured nanocrystalline alloys show excellent mechanical properties, and this metal bonding approach provides an important contribution to metal bonding and joining manufacturing techniques.