Copper and magnesium
Together form the Al₂CuMg (S-phase) precipitates that give strength after quenching and ageing. The high Mg:Cu ratio favours stability at moderately elevated temperatures.
GOST / OST aerospace alloy
Д19ч Aluminium Alloy
Д19ч is a Russian high-purity aluminium-copper-magnesium alloy of the duralumin family, a cleaner version of Д19 with tight limits on iron and silicon and a trace beryllium addition. Its higher magnesium content than Д16 gives good strength at moderately elevated temperatures, and its purity improves toughness and fatigue behaviour. It is supplied as sheet, plate, panels and extrusions under aerospace OST documents and GOST product standards.
- System
- Al-Cu-Mg-Mn (2xxx type)
- Suffix "ч"
- High purity (low Fe, Si)
- Conditions
- М, Т, Т1
- Closest Western types
- 2024 / 2124 (not identical)
What is Д19ч?
In the Russian letter system, "Д" denotes duralumin, the Al-Cu-Mg alloys first developed for aircraft, and the number identifies the variant: Д1 is the original duralumin, Д16 the high-strength workhorse comparable to 2024, and Д19 a higher-magnesium variant intended for better performance at elevated temperature. The suffix "ч" (from чистый, "pure") marks a high-purity version with reduced iron and silicon.
Iron and silicon form coarse intermetallic particles that start cracks and reduce toughness. Holding them to about 0.3 % and 0.2 % respectively, as in Д19ч, gives better fracture toughness, fatigue and formability than standard Д19 without changing the strengthening mechanism. The small beryllium addition protects the magnesium-rich melt from oxidation during casting; it plays no structural role in the finished product.
Д19ч is used mainly in aviation: skin and structural panels, ribbed extruded panels and machined parts on aircraft designed to Russian material specifications, and in repairs and replacement parts for those aircraft.
Д19ч chemical composition
Limits commonly quoted for Д19ч from the aerospace documents (OST 1 90048 and related specifications) are shown with the registered 2024 limits for comparison. Order and accept to the composition in the governing specification and the mill certificate.
| Element (%) | Д19ч | 2024 (AA) |
|---|---|---|
| Copper (Cu) | 3.8 – 4.3 | 3.8 – 4.9 |
| Magnesium (Mg) | 1.7 – 2.3 | 1.2 – 1.8 |
| Manganese (Mn) | 0.4 – 0.9 | 0.30 – 0.9 |
| Silicon (Si), max | 0.20 | 0.50 |
| Iron (Fe), max | 0.30 | 0.50 |
| Titanium (Ti), max | 0.10 | 0.15 |
| Zinc (Zn), max | 0.10 | 0.25 |
| Beryllium (Be) | 0.0002 – 0.005 | — |
| Others, each / total | 0.05 / 0.10 | 0.05 / 0.15 |
| Aluminium | Remainder | Remainder |
Manganese
Forms dispersoids that control grain structure during hot working and heat treatment.
Low Fe and Si
Fewer coarse intermetallics, so better toughness, fatigue crack growth resistance and bendability.
Standards and specifications
| Document | Covers |
|---|---|
| OST 1 90048 | Chemical composition of aviation aluminium alloys including Д19ч |
| GOST 4784 | Grades of wrought aluminium and aluminium alloys (general reference) |
| OST 1 90246, OST 1 90070 and related | Sheet supply for aviation, including Д19ч sheet |
| OST 1 90177 | Pressed (extruded) panels |
| OST 1 92041 | Ribbed extruded panels |
| GOST 21631 | Aluminium and alloy sheet (general product standard) |
OST documents are Russian aerospace industry standards and are not always openly available. Buyers working to them should supply the edition and any programme-specific technical conditions (ТУ) with the enquiry.
Supply conditions
| Condition | Meaning | Nearest Western temper |
|---|---|---|
| М | Annealed: soft, for forming | O |
| Т | Solution treated, quenched and naturally aged | T3 / T4 / T351 family |
| Т1 | Solution treated, quenched and artificially aged | T6 / T8 family |
| А (prefix or suffix on sheet) | Clad with pure aluminium for corrosion protection | Alclad |
Mechanical properties depend strongly on product form, thickness, test direction and condition. Aerospace documents give guaranteed minimums for each case, for example separate values for longitudinal and transverse specimens of panels. In general Д19ч in condition Т falls in the same strength class as Д16Т and 2024-T3. Density is about 2.76 g/cm³ and the elastic modulus about 70 GPa, typical of Al-Cu-Mg alloys.
Use only the guaranteed values from the governing OST or contract specification for design, and verify them on the mill certificate.
Product forms
Sheet and thin plate
Clad or bare sheet for skins, panels and formed parts, typically up to about 10 mm, in conditions М, Т or Т1.
Extruded and ribbed panels
Integrally stiffened panels for wing and fuselage structure, supplied to OST panel specifications.
Strip, flat bar and profiles
For stringers, supports, spacers and machined parts.
Western alternatives and substitution
There is no exact Western equivalent. 2024 has a similar copper level but less magnesium; 2124 and 2324 share the high-purity idea and are used where toughness matters in plate. Where the design authority allows substitution, 2024-T3 or 2524-T3 sheet and 2124-T851 plate are the usual starting points. Substitution on certified aircraft requires formal approval.
- Compare guaranteed minimum properties in each test direction, not typical values
- Check elevated-temperature requirements, which motivated Д19 in the first place
- Match cladding type and thickness for sheet
- Agree corrosion protection, since all Al-Cu-Mg alloys need cladding, anodising or primers
References and standards
- GOST 4784-97 – Aluminium and wrought aluminium alloys. Grades
- OST 1 90246-77 – Aviation sheet (references Д16ч, Д19, Д19ч sheet to OST 1 90048)
- ASTM B209 – Standard Specification for Aluminum and Aluminum-Alloy Sheet and Plate
- The Aluminum Association – International Alloy Designations and Chemical Composition Limits
Д19ч aluminium (aluminum) alloy: frequently asked questions
What does "ч" mean in Д19ч?
It stands for чистый, "pure": a high-purity version of Д19 with iron held to about 0.30 % and silicon to about 0.20 %, which improves toughness and fatigue behaviour.
How does Д19ч differ from Д16?
Д19ч has more magnesium (1.7 – 2.3 % against 1.2 – 1.8 %), slightly narrower copper, much lower impurities and a trace of beryllium. It was developed for better performance at moderately elevated temperatures.
Why does Д19ч contain beryllium?
A few thousandths of a percent of beryllium reduce oxidation of the magnesium-rich melt during casting. It has no structural purpose in the finished product.
What is the Western equivalent of Д19ч?
None is exact. 2024 and the high-purity 2124 and 2524 are the usual comparisons; substitution in aircraft needs approval by the design authority.
Can Metline supply Д19ч?
We review Д19ч enquiries case by case and supply approved Al-Cu-Mg alternatives such as 2024 and 2124 to international standards, with mill certificates and export documents.
Need Д19ч or an approved substitute?
Send the specification, form, condition and quantity. We will reply with availability and certification.
