If you’re sourcing cast parts, two choices drive everything: the casting process (die casting, permanent-mold, sand, investment) and the casting alloy (aluminum, zinc, magnesium, copper-base). This page gives you a clean, cross-process view so you can pick the right material system for your part’s geometry, finish, durability, and cost targets.
Unlike single-metal articles, this overview intentionally compares die-cast materials side-by-side. We explain what people mean by “die-cast metal,” when to use aluminum die cast alloys (A380/ADC12/AlSi10Mg), and when zinc (Zamak), magnesium (AZ91D/AM60), or copper/brass/bronze are a better fit. You’ll also find quick selectors, concise tables, and buyer-ready checklists you can send with drawings.
What Is a Casting Alloy vs “Die-Cast Metal”?
- Casting alloy = an engineered metal composition formulated to fill, solidify, and perform in a specific casting process.
- Die-cast metal = a product/process term: parts made by forcing molten metal into steel dies under pressure.
- Why it matters: fluidity, solidification range, hot-cracking tendency, pressure tightness, and achievable finish vary by both alloy and process, so the same geometry can demand a different alloy if you switch processes.
Which Casting Process Changes Alloy Choice (and Why)?
Die Casting (high-pressure)
- Where it shines: thin walls, high output, crisp cosmetics, good dimensional repeatability.
- Typical metals: Aluminum (A380/ADC12/AlSi10Mg), Zinc (Zamak 3/5), Magnesium (AZ91D/AM60).
- Watch-outs: venting/porosity control for pressure-tight parts; draft and parting strategy dominate yield.
Permanent-Mold / Gravity & Low-Pressure
- Where it shines: better ductility than HPDC, stable properties, good as-cast surfaces.
- Typical metals: Aluminum families; some bronzes.
- Watch-outs: thicker minimum wall; cycle time vs die casting.
Sand Casting
- Where it shines: large parts, low tooling cost, versatile shapes, easy gating changes.
- Typical metals: Aluminum, copper-base alloys.
- Watch-outs: rougher surfaces, more machining, slower throughput.
Investment Casting
- Where it shines: highly complex geometries, thin sections, excellent detail fidelity.
- Typical metals: Stainless, cobalt, nickel… plus selected aluminum and copper alloys.
- Watch-outs: longest lead time/cycle; cost per piece is higher but saves machining for intricate forms.
Cross-Process Snapshot: What Metals Work Where?
| Process ↓ / Metal → | Aluminum | Zinc (Zamak) | Magnesium | Copper/Brass/Bronze |
|---|---|---|---|---|
| Die Casting | ✓ A380 / ADC12 / AlSi10Mg | ✓ Zamak-3 / Zamak-5 | ✓ AZ91D / AM60 | ✓ selective bronzes |
| Permanent-Mold | ✓ common Al grades | – | – | ✓ some bronzes |
| Sand Casting | ✓ Al sand grades | – | – | ✓ brass/bronze family |
| Investment Casting | ✓ selected Al | – | – | ✓ copper-base & others |
Use the table to narrow your lane, then apply the quick alloy selector below.
Casting Alloy Comparison: Aluminum vs Zinc vs Magnesium vs Copper
| Metal | Strength-to-Weight | Thin-Wall Ability | Pressure-Tightness | Corrosion Behavior | Cosmetic Finish | Typical Part Size | Common Uses |
|---|---|---|---|---|---|---|---|
| Aluminum | good | very good | good (may need impregnation) | good with coat | powder/e-coat; limited anodic options for HPDC | S–XL | enclosures, brackets, lighting, auto |
| Zinc (Zamak) | fair (dense) | excellent (micro-features) | excellent | good indoors | class-A plating/paint | XS–M | small precision parts, hinges, gears |
| Magnesium | best | very good | good | needs coating; galvanic care | paint/e-coat | S–M | ultralight housings, EMI covers |
| Copper/Brass/Bronze | high | fair | very good | excellent (many grades) | plating/paint | S–L | wear parts, valves, conductive hardware |
*Relative Cost is indicative only; tooling, cycle time, and yield often dominate total cost.
When Should You Choose Aluminum Die Cast Alloys (and When Not)?
Pick aluminum if you need:
- Best cost/weight/finish balance for S–XL housings and brackets
- Broad supplier base, good cosmetics with powder/e-coat, good machinability
- Reasonable pressure tightness (with proper gating/impregnation where required)
Consider other metals when:
- Very small, micro-feature, tight-tolerance parts → Zamak often outperforms on wall control and flash management
- Extreme light-weighting / EMI shielding → Magnesium (with proper coating & design discipline)
- Wear, conductivity, seawater or chemicals → Copper-base alloys
Aluminum, Zinc, Magnesium & Copper — Quick Alloy Selector
| Alloy | Short Traits | Typical Uses | Notes |
|---|---|---|---|
| A380 (Al) | great castability, balanced strength & cost | general housings, brackets, heat-dissipating covers | global default for HPDC |
| ADC12 (Al) | very similar to A380; easy flow & finishing | electronics housings, lighting, auto interior | widely available in Asia/EU |
| AlSi10Mg (Al) | stronger Al; better elongation/thermal | structural light parts, aerospace-adjacent | tighter process window |
| Zamak-3 (Zn) | best stability, thin-wall champion | tiny hinges, gearboxes, precision levers | class-A plating capable |
| Zamak-5 (Zn) | higher strength than Zamak-3 | clips, buckles, small mechanisms | slightly less ductile |
| AZ91D (Mg) | lightest common die-cast alloy | laptop shells, handhelds, EMI covers | careful corrosion design |
| AM60 (Mg) | better ductility than AZ91D | energy-absorbing frames | auto/transport light-weighting |
| C83600 Bronze | wear + machinability | bushings, valves, pump parts | castable in sand/permanent-mold |
Already working with A380/ADC12/AlSi10Mg? We can sanity-check draft, gating, and tolerance against your geometry and volumes.
How Do Material Choice, Finish & Cost Interact?
- Cost stack: alloy price × shot weight/yield × cycle time × die complexity (slides/cores) × post-processing (deburr, impregnation, coat).
- Finish reality: as-cast Ra differs by metal/process; powder/e-coat hides minor texture; plating favors zinc; anodizing options differ for die-cast vs wrought aluminum.
- Tolerance & yield: zinc enables very stable thin walls; aluminum balances tolerance with weight and size; magnesium helps weight but needs robust corrosion strategy.
What Specs Do We Need to Recommend the Right Die Cast Alloy?
Send your RFQ with:
- 3D CAD (STEP/Parasolid), 2D with GD&T; identify cosmetic faces and target Ra
- Annual volume & ramp plan; target piece price or cost band
- Key requirements: pressure tightness, mechanical, thermal, EMI, conductivity, weight
- Operating environment: temperature range, fluids/chemicals, salt/fog, UV, sterilization
- Compliance: RoHS/REACH, automotive, appliance, food-contact (if applicable)
FAQs on Casting Alloys & Die-Cast Materials
What exactly is a “casting alloy,” and how is it different from “die-cast metal”?
Answer: An alloy is the material system; die-cast metal refers to parts made by the HPDC process using that alloy.
Which die cast alloy is best for very thin walls?
Answer: Zinc (Zamak-3/5) typically wins for extreme thin-wall precision; aluminum follows closely; magnesium is good when wall is thin and weight is critical.
How do A380 and ADC12 differ for buyers?
Answer: They’re very close in properties and castability; selection is often driven by region, foundry preference, and finishing expectations.
Can aluminum die casting be pressure-tight?
Answer: Yes, with correct gating/venting and, for demanding applications, impregnation and robust leak testing.
Which alloys take the best cosmetic finish?
Answer: Zinc for bright plating; aluminum for powder/e-coat (and selective anodic finishes depending on spec); magnesium requires a qualified coating stack.
What should I send for a fast material recommendation?
Answer: CAD, annual volume, cosmetic/finish target, environment, and any pressure-tight or mechanical test requirements.
Need a Supplier to Review Your Drawing & Alloy Choice?
We’ve supplied cast parts for automotive, lighting, furniture, appliances, and electrical enclosures for 20+ years. Share your CAD + requirements and we’ll recommend an alloy/process combination and flag risks early (draft, thin-wall feasibility, gating, tolerance and finish). Send your files and target outcomes — we’ll get you practical feedback.
