AZ31B vs AZ91D: 59% composition overlap. Moderate differences, generally not direct substitutes.
AZ31B vs AZ91D
Side-by-side chemical composition and mechanical property comparison.
Overview
AZ31B
M11311
The most widely used wrought magnesium alloy. Available as sheet, plate, bar, and extrusion. 3% Al + 1% Zn gives good room-temperature strength and ductility with excellent weldability (TIG/MIG). Density 1.78 g/cm³. An alternative to aluminum where weight reduction is critical. Used for aircraft fuselage panels, electronic device housings (laptops, smartphones), lightweight jigs and fixtures, vibration-damping components, and rapid prototyping. Strain-hardened tempers (H24, H26) provide higher strength. DIN: 3.5312.
AZ91D
M11916
The most widely used magnesium die casting alloy worldwide. High-purity variant (D suffix) with strict Fe, Ni, Cu limits for excellent corrosion resistance. 9% Al + 1% Zn provides good castability, strength, and dimensional stability. Density only 1.81 g/cm³ — 35% lighter than aluminum. Not weldable. Used for automotive transmission cases, engine covers, steering components, laptop and smartphone housings, power tool casings, and camera bodies. The industry standard for Mg die casting. DIN: 3.5912, EN: MC 21120.
| AZ31B | AZ91D | |
|---|---|---|
| Material Number | M11311 | M11916 |
| Category | magnesium | magnesium |
| Standard | ASTM B90 | ASTM B94 |
Chemical composition (wt%)
| Element | AZ31B | AZ91D | Overlap |
|---|---|---|---|
| Si | ≤ 0.1% | ≤ 0.1% | OK |
| Mn | 0.2–1% | 0.15–0.5% | Partial |
| Ni | ≤ 0.005% | ≤ 0.002% | OK |
| Cu | ≤ 0.05% | ≤ 0.03% | OK |
Mechanical properties
| Property | AZ31B | AZ91D | Unit |
|---|---|---|---|
| tensile_strength | 250–290 | 230–280 | MPa |
| yield_strength | 180–220 | 160–220 | MPa |
| elongation | 6–12 | 3–7 | % |
Compatibility Assessment
AZ31B and AZ91D have moderate differences (59% overlap). They are generally not direct substitutes. Consider the specific requirements of your application.
Automated assessment based on composition analysis
Frequently Asked Questions
Is AZ31B the same as AZ91D?
AZ31B and AZ91D have a 59% composition overlap. They are generally not directly interchangeable.
Can I replace AZ31B with AZ91D?
Generally not recommended. The compositions differ significantly (59% overlap). These materials have different alloying concepts and are intended for different applications.
What is the difference between AZ31B and AZ91D?
The main differences are in the following elements: Mn, Al, Zn. AZ31B is a magnesium grade, while AZ91D is a magnesium grade.
View full data for each material:
Data provided for reference only. Always verify against the applicable specification for critical applications.
All data is for reference only. Equivalents indicate similarity, not identity. Always verify against the applicable specification for safety-critical applications. materialref.com accepts no liability for decisions based on this data.