ZL118 (ZAlSi5Cu1MgA) Cast Aluminum Alloy: A high purity, multi-strengthened alloy with high strength, good heat resistance and aerospace grade reliability.
Date: 2026-03-13 Categories: Blog Views: 49
As a Chinese national standard (GB/T 1173) in theAluminum-silicon-copper-magnesium high-strength casting alloywhich represents a high-purity upgrade.ZL118 (ZAlSi5Cu1MgA) by means ofHigh room temperature strength, excellent high temperature performance, good castability and aerospace grade reliabilityand is well known. This alloy is the ZL105high purity versionBy means of theStrict limitation of the content of impurity elements (especially iron)ZL105 can be used in the manufacture of aluminum-copper alloys, which can maintain the good casting performance of ZL105 and significantly improve the mechanical properties, elongation and batch stability, and can obtain the high strength level close to that of aluminum-copper alloys after T6 heat treatment, and at the same time, retains better casting workmanship than that of aluminum-copper alloys.Key castings in the field of aviation, aerospace and high-end equipment that are subject to high loads and require high reliability.The ideal material for the
The national grade for ZL118 is ZAlSi5Cu1MgA.
- National Standard Grade: According to GB/T 1173, its grade isZAlSi5Cu1MgAThe name directly reflects the core alloy system: silicon (Si), copper (Cu) and magnesium (Mg). The name is a direct reflection of the core alloy system: silicon (Si), copper (Cu) and magnesium (Mg), with the suffix “A” standing for the high-purity version.
- Industry/Enterprise Code:ZL118 It is a widely used designation for this material in drawings, manuals and enterprise standards in the field of aviation, aerospace and high-end casting.
- Core features:Low to medium silicon content (4.5-5.51 TP3T) Ensure basic casting fluidity;Copper (1.0-1.5%) composite with magnesium (0.4-0.6%)Provide multiple reinforcement effects;Extremely strict impurity control (iron ≤ 0.15%) is its core advantage, significantly improving mechanical properties and reliability; after T6 heat treatment to obtain theBalance of high strength and good heat resistance.
ZL118 Aluminum Alloy Composition Table (based on GB/T 1173 typical requirements)
| elemental | Content range (wt%) | functional role |
|---|---|---|
| Silicon (Si) | 4.5-5.5 | Primary alloying element. Provides basic casting fluidity, partially solid solution strengthened. |
| Copper (Cu) | 1.0-1.5 | Core strengthening element. Forms Al₂Cu reinforced phases, which significantly increase room and high temperature strength. |
| Magnesium (Mg) | 0.4-0.6 | Key strengthening element. Forms Mg₂Si with silicon and synergizes with copper to produce a composite strengthening effect. |
| Iron (Fe) | ≤ 0.15 | The most critical point of difference in impurities. Compared with ZL105 (Fe≤0.5%), the iron content is significantly reduced, significantly reducing brittle phases and improving plasticity and fatigue properties. |
| Manganese (Mn) | 0.3-0.5 (can be added) | Neutralizes the harmful effects of residual iron and improves heat resistance. |
| Titanium (Ti) | 0.1-0.2 (can be added) | Grain refiner. |
| Zinc (Zn) | ≤ 0.1 | Impurities. Strictly controlled. |
| Aluminum (Al) | tolerance (i.e. allowed error) | Substrate material. |
ZL118 Physical and Mechanical Properties Parameter Table (metal mold casting, typical values)
| Performance indicators | Cast (F) | T5 aging state | T6 solid solution + aging state | Performance Positioning and Interpretation |
|---|---|---|---|---|
| intensity | 2.68-2.70 g/cm³ | -- | -- | -- |
| Tensile strength (Rm) | 180-220 MPa | 260-300 MPa | 320-360 MPa | Excellent strength in T6 stateIt has reached the top level of high-strength cast aluminum. |
| Yield strength (Rp0.2) | 100-130 MPa | 200-230 MPa | 260-300 MPa | The yield strength is greatly increased after heat treatment, and the load carrying capacity is high. |
| Elongation (A) | 2.0-4.0% | 2.0-3.0% | 3.0-5.0% | Core Advantages: Compared with ZL105 (elongation 1.5-3.0%), the plasticity is significantly improved. |
| Brinell hardness (HB) | 60-70 | 90-100 | 100-115 | High hardness and good abrasion resistance. |
| High Temperature Strength (250°C) | favorable | talented | talented | Copper-magnesium composite allows it to maintain excellent high-temperature performance. |
| Casting mobility | moderate | -- | -- | Lower silicon content and less fluidity than high silicon alloys. |
| corrosion resistance | moderate | moderate | moderate | The copper content makes them less resistant to corrosion than copper-free alloys. |
| Batch Stability | favorable | favorable | talented | Strict impurity control for better performance consistency. |
Performance Enhancement Pathways and Technical Characteristics
The ZL118“s performance comes from its "Multi-Compound Enhancement + High Purification Upgrade”The Technical Route:
- Copper-magnesium composite reinforcement: The ratio of copper (1.0-1.5%) to magnesium (0.4-0.6%) is optimized to obtain after T6 heat treatmentAl₂Cu and Mg₂Si double reinforced phasesThe synergistic effect results in a significant increase in strength and a uniform distribution of reinforcing phases, while maintaining good high temperature properties.
- High purity upgrade: Reduce iron content from ≤0.5% in ZL105 to≤0.15%, which drastically reduces the formation of the acicular brittle iron-rich phase, which is itsDoubled elongation and improved fatigue performanceThe root cause of the
- Excellent heat treatment responsiveness:
- T5 (artificial aging): For applications where high dimensional stability is required and the risk of deformation needs to be minimized.
- T6 (solid solution + full artificial aging): To obtain peak strength, suitable for load-bearing structural members.
- Typical T6 process: 515-525°C × 6-12 hours solid solution, warm water (60-80°C) quenching, 160-180°C × 6-10 hours aging.
- Strict quality control: Strict requirements for the purity of primary aluminum, the melting process, and the heat treatment process are in place to ensure thatBatch-to-batch performance consistency, meets aerospace grade reliability requirements.
Corresponding international grades
ZL118 as a high purity version of ZL105 has a clear international counterpart:
| (an official) standard | grades | note |
|---|---|---|
| China GB/T 1173 | ZL118 (ZAlSi5Cu1MgA) | High purity version of ZL105, Fe≤0.15% |
| ASTM, USA | A355.0 或 354.0 | A355.0 is close in composition, 354.0 has higher silicon content |
| EU EN | EN AC-45200 (AlSi5Cu1Mg) | Need to use high-purity grade, corresponding to iron ≤ 0.15% |
| France NF | A-S5U | Partial high purity version |
| ISO 3522 | AlSi5Cu1Mg | High purity grade required |
ZL118 in the foundry industry
based on itsHigh strength, excellent high temperature performance, good plasticity and aerospace grade reliabilityfeatures, ZL118 is mainly used in the following fields:
- Aerospace and Defense (Core Applications)
- Aircraft structural parts: Stress braces, joints, frames, hatch rails, landing gear components.
- Engine components: Compressor receiver, accessory drive housing, fuel pump housing, intake manifold.
- Missile components: Rudder mounts, instrument bay structural members, connecting rings.
- High Performance Cars and Racing Cars
- Engine components: High-performance cylinder heads, pistons (not in the highest heat load area), intake manifolds.
- transmission system: Transmission housing, clutch housing, distributor housing.
- pressurization system: Turbocharger intermediate housing, compressor housing.
- Railway transportation and heavy equipment
- High-speed railway bogie parts, heavy truck transmission shell, engineering machinery hydraulic valve body.
- High-end civilian equipment
- Compressor blocks, high-pressure pump bodies, and industrial robot components requiring high reliability.
ZL118 Aluminum Alloy Frequently Asked Questions
Q1: What is the main difference between ZL118 and ZL105? How to select the model?
- This is the central comparison:
- ZL105: Basic version, iron content ≤ 0.5%.quality-price ratioThe strength meets most industrial applications with an elongation of 1.5-3.01 TP3T.
- ZL118: High purity version, iron content ≤ 0.15%.Significant performance improvementsThe elongation is up to 3.0-5.0% with better fatigue performance and batch stability.
- selection: Selection of conventional industrial applicationsZL105; aerospace, defense, high-performance automotive, etc. on theHigh reliability and toughness requirementsThe occasion of the selection of theZL118.
Q2: How much more expensive is the ZL118 than the ZL105? Is the performance increase worth it?
- Costs are usually higher20-30%, mainly stemming from stricter requirements for primary aluminum purity, melting process control and testing.
- whether it's worthwhileDepending on the application: for general industrial machinery, the performance of ZL105 is sufficient; however, for aerospace, racing cars, etc., the performance of ZL105 is sufficient.Reliability and fatigue life are demandingoccasions, the performance improvement of ZL118 ismust haveIt pays a premium for “reliability”. It pays a premium for "reliability".
Q3: What is the difference between the heat treatment process of ZL118 and ZL105?
- Same basic parametersHowever, ZL118 has less impurities, uniform organization, and heat treatment.Wider window for better performance consistency. With the same process, ZL118 always achieves better properties, especially elongation.
Q4: What is the casting performance of ZL118? How does it compare with ZL105?
- Comparable to ZL105. With the same silicon content (4.5-5.51 TP3T), the fluidity is sufficient for most castings of medium complexity. However, it should be noted that its fluidity is not as good as high silicon alloys such as ZL104, ZL111, etc. The pouring system should be optimized when designing thin-walled parts.
Q5: What is the welding repair performance of ZL118?
- Upper middle class. Moderate copper content (1.0-1.5%), welding hot cracking tendency is lower than ZL107 and other high copper alloys. For argon arc welding filler welding, it is recommended toPreheating (100-150°C)The same quality of wire is used, and the welding is performed after welding.stress relief. High purity makes its weld quality more stable.
Q6: What is the corrosion resistance of ZL118? Does it need surface treatment?
- moderateThe copper content makes it less resistant to corrosion than copper-free ZL101A, ZL104. The copper content makes it less resistant to corrosion than the copper-free ZL101A, ZL104. used outdoors or in wet environments.Surface protection is recommended, such as painting, anodizing (the film layer may be grayish), etc..
Q7：Can ZL118 be used instead of imported A355.0?
- canZL118 highly corresponds to A355.0 in terms of composition and properties, and is an ideal replacement material for localization. However, it is necessary to confirm whether the specific performance indexes (especially elongation and fatigue strength) meet the design requirements and fully verify them.
📊 Extended Column: Comparative Analysis of ZL118 and ZL105 and Related Alloys
| comparison dimension | ZL118 (High purity version) | ZL105 (Basic) | ZL101A (Copper-free high purity) | ZL114A (high magnesium, high purity) |
|---|---|---|---|---|
| Silicon (Si)% | 4.5-5.5 | 4.5-5.5 | 6.5-7.5 | 6.5-7.5 |
| Copper (Cu)% | 1.0-1.5 | 1.0-1.5 | ≤0.1 (without copper) | ≤0.1 (without copper) |
| Magnesium (Mg)% | 0.4-0.6 | 0.4-0.6 | 0.25-0.45 | 0.45-0.75 |
| Iron (Fe)% | ≤0.15 | ≤0.5 | ≤0.20 | ≤0.15 |
| Tensile strength (T6) | 320-360 MPa | 280-320 MPa | 290-330 MPa | 320-370 MPa |
| Yield strength (T6) | 260-300 MPa | 210-250 MPa | 220-260 MPa | 260-300 MPa |
| Elongation (T6) | 3.0-5.0% | 1.5-3.0% | 3.0-6.0% | 5.0-10.0% |
| High Temperature Strength | talented | favorable | favorable | favorable |
| Casting mobility | moderate | moderate | favorable | favorable |
| Typical Costs | high-end | moderate | mid-to-high-end | high-end |
Selection Quick Guide:
- Select ZL118: When the part requiresHigh strength, excellent high temperature performance, good plasticityWhen reliability is required (aero-engine accessories, high-performance automotive components).
- Select ZL105: Conventional industrial applications when strength is required but cost is sensitive.
- Select ZL101A: When a combination of high strength and good corrosion resistance is required and the working temperature is moderate.
- Select ZL114A: The QuestUltimate strength and toughnessWhen heat resistance is not required.
