Abstract Orthogonal thermomechanical processes consisting of a hot extrusion and the subsequent orthogonal rolling are proposed to disperse the nanoparticle clusters and optimize the grain structures of matrices in in-situ synthesized TiB2 particles reinforced Al-Zn-Mg-Cu composites. The particle distributions and grain structures of composites are investigated by scanning electron microscopy, electron backscatter diffraction and neutron diffraction techniques. Compared with the hot extruded counterparts, the composites fabricated by the new process exhibit uniform particle distributions, less elongated grains and weak textures, owing to the strain path change and enhanced recrystallizations. Both high strength (669 MPa and 606 MPa) and good ductility (11.1% and 14.2%), are achieved in the resultant composites along the longitudinal and transverse direction respectively. The underlying mechanisms for modified mechanical properties are discussed in detail from the perspectives of the uniform TiB2 particles and homogenized grain structures.

中文翻译：

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正交热机械工艺后纳米颗粒增强铝复合材料的结构均匀性和机械性能的改善

摘要 提出了由热挤压和随后的正交轧制组成的正交热机械工艺来分散纳米颗粒簇并优化原位合成的 TiB2 颗粒增强 Al-Zn-Mg-Cu 复合材料中基体的晶粒结构。通过扫描电子显微镜、电子背散射衍射和中子衍射技术研究了复合材料的颗粒分布和晶粒结构。与热挤压复合材料相比，由于应变路径变化和增强的再结晶，采用新工艺制造的复合材料表现出均匀的颗粒分布、较少的细长晶粒和较弱的织构。兼具高强度（669 MPa 和 606 MPa）和良好的延展性（11.1% 和 14.2%），分别沿纵向和横向在所得复合材料中实现。从均匀的 TiB2 颗粒和均质化的晶粒结构的角度详细讨论了改进机械性能的潜在机制。