Scholarlink

<p>This study investigates the effects of praseodymium (Pr) addition and multi-step T6 heat treatment on the microstructural features and mechanical properties of 7075 Al-Zn-Mg-Cu alloys. The alloys were prepared by gravity casting using a preheated (250 °C) metallic mold with a cooling rate of 10°C/s, followed by a multi-step T6 treatment consisting of: (1) homogenization at 500°C for 8 h, (2) solution treatment at 470 °C for 2 h with water quenching, and (3) three-stage aging (100 °C/1h + 120 °C/1.5h + 150 °C/2.17h).The findings indicate that Pr addition significantly influences the alloy’s performance by altering grain structure, intermetallic phase formation, and precipitation behavior. The hardness of the alloy was increased by 33.3% after heat treatment, with a 13.6% increase observed at 1.0 wt.% Pr. However, the latter's lower hardness enhancement was attributed to the formation of coarse intermetallic phases, which do not strengthen the alloy and may potentially weaken its structure. The best compressive properties were achieved with 0.5 wt.% Pr, where heat treatment resulted in a 75.6% increase in yield strength and a 13.34% increase in ductility. In contrast, higher Pr content (1.0 wt.%) led to a reduction in both properties, demonstrating the importance of optimizing Pr content. The highest ultimate compressive strength (UCS) was recorded at 536.82 MPa at 0.5 wt.% Pr after heat treatment, whereas further Pr addition (1.0 wt.%) caused a decrease in UCS. Microstructural observations revealed that 0.5 wt.% Pr refined grain size and promoted a homogeneous dispersion of fine precipitates, enhancing mechanical properties. On the other hand, 1.0 wt.% Pr led to microstructural coarsening and increased intermetallic phase formation, which introduced stress concentration sites and compromised ductility despite the highest hardness. These results emphasize that a balanced Pr addition, along with optimized heat treatment, significantly improves the mechanical properties of 7075 alloys for advanced structural applications.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Influence of Praseodymium Additions and Multiple Step T6 on Microstructure, and Mechanical Properties of 7075 Al-Zn-Mg-Cu Alloy

  • 期刊论文

  • 发表日期：

    2025年9月9日

查看全文
  • M. G. Mahmoud,
  • Ahmed O. Mosleh,
  • S. Salem,
  • Wesam M. Sadek,
  • Olga A. Yakovtseva,
  • Waleed Khalifa,
  • Andrey V. Pozdniakov,
  • Sabbah Ataya,
  • Fahamsyah H. Latief

摘要

This study investigates the effects of praseodymium (Pr) addition and multi-step T6 heat treatment on the microstructural features and mechanical properties of 7075 Al-Zn-Mg-Cu alloys. The alloys were prepared by gravity casting using a preheated (250 °C) metallic mold with a cooling rate of 10°C/s, followed by a multi-step T6 treatment consisting of: (1) homogenization at 500°C for 8 h, (2) solution treatment at 470 °C for 2 h with water quenching, and (3) three-stage aging (100 °C/1h + 120 °C/1.5h + 150 °C/2.17h).The findings indicate that Pr addition significantly influences the alloy’s performance by altering grain structure, intermetallic phase formation, and precipitation behavior. The hardness of the alloy was increased by 33.3% after heat treatment, with a 13.6% increase observed at 1.0 wt.% Pr. However, the latter's lower hardness enhancement was attributed to the formation of coarse intermetallic phases, which do not strengthen the alloy and may potentially weaken its structure. The best compressive properties were achieved with 0.5 wt.% Pr, where heat treatment resulted in a 75.6% increase in yield strength and a 13.34% increase in ductility. In contrast, higher Pr content (1.0 wt.%) led to a reduction in both properties, demonstrating the importance of optimizing Pr content. The highest ultimate compressive strength (UCS) was recorded at 536.82 MPa at 0.5 wt.% Pr after heat treatment, whereas further Pr addition (1.0 wt.%) caused a decrease in UCS. Microstructural observations revealed that 0.5 wt.% Pr refined grain size and promoted a homogeneous dispersion of fine precipitates, enhancing mechanical properties. On the other hand, 1.0 wt.% Pr led to microstructural coarsening and increased intermetallic phase formation, which introduced stress concentration sites and compromised ductility despite the highest hardness. These results emphasize that a balanced Pr addition, along with optimized heat treatment, significantly improves the mechanical properties of 7075 alloys for advanced structural applications.