Effect of tempering on case hardening aluminum 7075 on its hardness

• Main Authors: Darsono, Febri Budi, Koin, Sudibtia Titio, Nurdin, Akhmad, Sudiyono, Sudiyono, Widodo, Rahmat Doni, Rusiyanto, Rusiyanto
• Format: Conference Proceeding
• Language: English
• Subjects: Aluminum; Aluminum carbide; Case hardening; Diamond pyramid hardness tests; Pack carburizing; Precipitates; Solution heat treatment; Temper (metallurgical); Tempering
• ISSN: 0094-243X; 1551-7616
• DOI: 10.1063/5.0122369

This study aims to determine the effect of tempering on the treatment of case hardening aluminum 7075 on its hardness. The stages of the tempering process are heating with a temperature of 120 °C for two days on aluminum that has been treated on case hardening (CH). The case hardening process uses the pack carburizing method, with variations in temperature of solution heat treatment (SHT): 350-500 °C, followed by a quenching process. The tests carried out include the Vickers hardness test, microstructure test, and XRD test. The results show the most excellent hardness in the temper case hardening (TCH) treatment and the case hardening (CH) treatment at SHT of 500 °C, namely 182.5 and 145.9 VHN. The increase of hardness in the temper case hardening (TCH) treatment was due to the formation of the Al4C3 phase. The hardness was evenly distributed from the surface edge to the core due to the formation of Al2CuMg and MgZn2 precipitates. Meanwhile, in the case of hardening (CH) treatment, the hardness was only on the surface edge, and the hardness decreased when it got to the core due to the Al4C3 phase was the only phase formed.