Precipitation processes during non-isothermal ageing of fine-grained 2024 alloy
PBN-AR
Instytucja
Wydział Metali Nieżelaznych (Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie)
Informacje podstawowe
Główny język publikacji
EN
Czasopismo
ARCHIVES OF METALLURGY AND MATERIALS
ISSN
1733-3490
EISSN
Wydawca
POLISH ACAD SCIENCES COMMITTEE METALLURGY and INSTITUTE OF METALLURGY AND MATERIALS SCIENCE
DOI
Rok publikacji
2016
Numer zeszytu
1
Strony od-do
169--176
Numer tomu
61
Link do pełnego tekstu
Identyfikator DOI
Liczba arkuszy
0.57
Autorzy
Pozostali autorzy
+ 2
Słowa kluczowe
EN
precipitation hardening
powder metallurgy
AA2024 alloy
scrap metal milling
structure refining
Streszczenia
Język
EN
Treść
Mechanical alloying and powder metallurgy procedures were used to manufacture very fine-grained bulk material made from chips of the 2024 aluminum alloy. Studies of solution treatment and precipitation hardening of as-received material were based on differential scanning calorimetry (DSC) tests and TEM/STEM/EDX structural observations. Structural observations complemented by literature data lead to the conclusion that in the case of highly refined structure of commercial 2024 alloys prepared by severe plastic deformation, typical multi-step G-P-B→θ”→θ’→θ precipitation mechanism accompanied with G-P-B→S”→S’→S precipitation sequences result in skipping the formation of metastable phases and direct growth of the stable phases. Exothermic effects on DSC characteristics, which are reported for precipitation sequences in commercial materials, were found to be reduced with increased milling time. Moreover, prolonged milling of 2024 chips was found to shift the exothermic peak to lower temperature with respect to the material produced by means of common metallurgy methods. This effect was concluded to result from preferred heterogeneous nucleation of particles at subboundaries and grain boundaries, enhanced by the boundary diffusion in highly refined structures. Transmission electron microscopy and diffraction pattern analysis revealed the development of very fine Al4C3 particles that grow due to the chemical reaction between the Al matrix and graphite flakes introduced as a process control agent during the preliminary milling of chips. Al4C3 nano-particles are formed at high temperatures, i.e. during hot extrusion and the subsequent solution treatment of the samples. Highly refined insoluble particles such as aluminum carbide particles and aluminum oxides were found to retard recrystallization and reduce recovery processes during solution treatment of preliminarily milled materials. Therefore, the as-extruded material composed of a milled part and chip residuals retained its initial bimodal structure in spite of solution heat treatment procedures. This points to a high structural stability of the investigated materials, which is commonly required for new technologies of high-strength Al-based materials production.
Cechy publikacji
original article
peer-reviewed
Inne
System-identifier
idp:096779
CrossrefMetadata from Crossref logo
Cytowania
Liczba prac cytujących tę pracę
Brak danych
Referencje
Liczba prac cytowanych przez tę pracę
Brak danych