Overview of Metal Materials for 3D Printing
3D 打印，又称 快速成型制造, allows for the creation of complex metal parts directly from 3D CAD data. In contrast to traditional subtractive methods like CNC machining, 3D printing builds up parts layer-by-layer without the need for dedicated tooling or fixtures.
Metal 3D printing opens up new possibilities for producing customized, lightweight, and high-performance metal components with complex geometries. Aerospace, automotive, medical, and defense industries are increasingly adopting metal 3D printing for end-use production applications.
However, not all metals can be easily 3D printed. The most commonly used metal materials are aluminum, titanium, nickel, stainless steel, and cobalt-chrome alloys. The choice of material depends on the specific application requirements – strength, corrosion resistance, high temperature performance, biocompatibility, etc.
This comprehensive guide provides a detailed overview of various metals and alloys used in 3D printing. We discuss the composition, properties, applications, and pros and cons of popular metal materials to help you select the right material for your needs.
Key Takeaways on Metal 3D Printing Materials:
- Aluminum alloys offer good strength-to-weight ratio and corrosion resistance at lower costs.
- Titanium alloys provide excellent strength with low density and biocompatibility for medical uses.
- Stainless steels have high strength and corrosion resistance for tooling and functional parts.
- Nickel superalloys can withstand high temperatures making them suitable for aerospace.
- Cobalt-chrome alloys provide hardness, wear resistance and biocompatibility for dental and medical implants.
- Material choice depends on mechanical requirements, post-processing needs, costs and 3D printing method suitability.
- Part orientation, support structures, layer thickness and build parameters need to be optimized for each metal material.
- Post-processing like hot isostatic pressing can enhance final part properties.
Composition of Metal Materials for 3D Printing
The composition of alloying elements in metals and the microstructure provides specific properties and determines the suitability of the material for 3D printing.
铝合金
Aluminum is known for its low density and good corrosion resistance. Wrought and cast aluminum alloys are most commonly used:
| 合金类型 | 作曲 |
|---|---|
| 6061 | Mg, Si, Cu, Cr |
| 7075 | Zn, Mg, Cu, Cr |
| A356 | Si, Mg, Cu |
6061 offers better corrosion resistance while 7075 has higher strength. A356 is a castable alloy.
钛合金
Titanium has high strength-to-weight ratio and bio-compatibility but can be difficult to machine. Common alloys:
| 合金类型 | 作曲 |
|---|---|
| 钛-6Al-4V | Al, V |
| Ti 6242 | Al, Sn |
Ti-6Al-4V offers the best balance of properties and is the most extensively used titanium alloy.
不锈钢
Stainless steels contain Cr and Ni for good corrosion resistance. Some alloys used:
| 合金类型 | 作曲 |
|---|---|
| 316L | Ni, Mo, Cr |
| 17-4PH | Ni, Cr, Cu |
| 303 | S, Cr, Ni |
316L provides excellent corrosion resistance. 17-4PH is precipitation hardening martensitic stainless steel.
镍超合金
Nickel superalloys have high strength and withstand extreme temperatures. Common alloys:
| 合金类型 | 作曲 |
|---|---|
| 铬镍铁合金 718 | 镍、铬、铁、铌、钼 |
| 铬镍铁合金 625 | 镍、铬、钼、铌 |
Inconel 718 is extensively used in aerospace applications. Inconel 625 has excellent corrosion resistance.
Cobalt-Chrome Alloys
Cobalt-chrome alloys provide hardness, wear resistance and biocompatibility. Two main grades used:
| 合金类型 | 作曲 |
|---|---|
| 钴铬钼合金 | Co, Cr, Mo |
| CoNiCrMo | Co, Ni, Cr, Mo |
Both provide similar properties. CoCrMo is more widely used.
Mechanical Properties of Metal Materials
The mechanical properties of the metal determine the performance of the 3D printed part. Below are typical properties of commonly used alloys:
| Metal Material | 屈服强度（兆帕） | 拉伸强度（兆帕） | 伸长（％） | 密度（克/立方厘米） |
|---|---|---|---|---|
| AlSi10Mg | 230 | 450 | 8 | 2.68 |
| 钛-6Al-4V | 880 | 930 | 10 | 4.43 |
| 316L 不锈钢 | 290 | 515 | 40 | 8 |
| 铬镍铁合金 718 | 1138 | 1275 | 12 | 8.19 |
| 铬镍铁合金 625 | 550 | 860 | 35 | 8.44 |
| 钴铬钼合金 | 655 | 860 | 8 | 8.3 |
- Aluminum alloys offer medium strength with excellent elongation.
- Titanium alloys provide very high strength considering their low density.
- Stainless steel 316L offers good ductility and excellent corrosion resistance.
- Inconel superalloys are extremely strong but less ductile.
- Cobalt chrome has high hardness making it difficult to machine after printing.
Applications of Metal 3D Printing
The choice of material depends on the end-use application and the specific design requirements:
| 行业 | 应用 | 所用材料 |
|---|---|---|
| 航空航天 | Turbine blades, structural brackets | Titanium alloys, Inconel, Stainless steel |
| 汽车 | Custom parts, tooling | Aluminum, Low alloy steel |
| 医疗 | 植入物、手术器械 | Titanium, Cobalt-chrome |
| 石油和天然气 | Valves, pumps, tooling | Stainless steel, Inconel |
| 国防 | Complex parts, lightweight armor | Aluminum, Titanium |
Some typical applications taking advantage of 3D printed metal parts:
- Aerospace: Complex and lightweight brackets and structural components
- Automotive: Customized parts for motorsports applications
- Medical: Patient-specific implants and surgical instrumentation
- Oil and gas: High-performance valves and pumps for pipelines
- Defense: Detailed and lightweight components for vehicles and equipment
Pros and Cons of Key Metal Materials
Here is a comparison of the advantages and limitations of popular metal alloys used in 3D printing:
| 材料 | 优点 | 缺点 |
|---|---|---|
| Aluminum 6061 | Low cost, good corrosion resistance | Lower strength |
| Aluminum 7075 | 高强度重量比 | Difficult to weld |
| 钛 Ti-6Al-4V | High strength, low density | Expensive material |
| Stainless Steel 316L | 卓越的耐腐蚀性 | Lower strength than alloys |
| 铬镍铁合金 718 | Withstands extreme temperatures | Challenging to machine |
| 钴铬合金 | Excellent wear and biocompatibility | Limited ductility |
Suppliers of Metal 3D Printing Materials
Many companies provide metal powders and wire specifically for 3D printing processes:
| 材料 | Key Suppliers |
|---|---|
| 铝合金 | AP&C, Sandvik, HC Starck |
| 钛合金 | AP&C, TLS Technik, Tekna |
| 不锈钢 | Sandvik, Carpenter Additive |
| 镍超合金 | AP&C, Sandvik, Praxair |
| Cobalt Chrome Alloys | AP&C, Sandvik, SLM Solutions |
Factors like powder quality, consistency, particle shape and size distribution affect final part properties and print process stability. Reputed suppliers provide well-characterized and customized alloys tailored for AM.
Cost Analysis of Metal 3D Printing Materials
Material costs constitute a significant portion of the final part cost in metal 3D printing. Below are approximate price ranges:
| 材料 | Cost per Kg | Cost per cm3 |
|---|---|---|
| 铝合金 | $50-$150 | $0.15-$0.45 |
| 钛合金 | $350-$1000 | $1.00-$3.00 |
| 不锈钢 | $90-$250 | $0.25-$0.75 |
| 铬镍铁合金 718 | $350-$600 | $2.50-$4.50 |
| 钴铬合金 | $500-$1200 | $3.50-$8.50 |
- Titanium and cobalt chrome alloys are the most expensive while aluminum is moderately priced.
- Material costs scale with build volume – larger parts in expensive alloys require higher material budgets.
- Optimization to reduce support waste and post-processing can help lower effective material costs.
Standards for Metal Powders
To ensure repeatable high quality prints, metal powders used in 3D printing must meet certain minimum standards:
| 物业 | Key Standards |
|---|---|
| 粒径分布 | ASTM B822, ISO 4490 |
| 流动性 | ASTM B213, ISO 4490 |
| 表观密度 | ASTM B212, ISO 3923 |
| 水龙头密度 | ASTM B527, ISO 3953 |
| 化学成分 | ASTM E1479, OES analysis |
- Powder quality influences final part properties like density, surface finish and mechanicals.
- Spherical powders with controlled particle size distribution have excellent flowability.
- Consistent chemistry and density provide process stability and repeatability.
3D Printing Methods for Metals
Various 3D printing technologies can process metals and alloys:
| 方法 | 材料 | Key Benefits | 局限性 |
|---|---|---|---|
| 粉末床融合 | 大多数合金 | 出色的精度和表面光洁度 | Slow build rates |
| 定向能量沉积 | 大多数合金 | Built-up features on existing parts | Lower resolution |
| 粘结剂喷射 | 不锈钢 | High speed printing | Lower strength |
| Metal Extrusion | 有限合金 | Low equipment costs | 密度较低 |
- Powder bed technologies like DMLS offer the highest resolution and accuracy.
- Binder jetting works with a wider range of alloys but has lower final part strength.
- Directed energy deposition allows printing of large near-net shape parts.
后期处理要求
As-printed metal parts typically require post-processing to achieve desired properties:
| Post-Process | 目的 | 所用材料 |
|---|---|---|
| 支持移除 | 拆除支撑结构 | Alloys with thin, fragile supports |
| 缓解压力 | Reduce residual stresses | All alloys |
| 热等静压 | Increase density, enhance properties | All alloys |
| 表面处理 | Improve surface roughness | All alloys |
| 热处理 | Modify microstructure | Age-hardenable alloys like aluminum |
| 加工 | Accurate dimensions and surface finish | 大多数合金 |
- Stress relieving heat treatment is recommended for all alloys to prevent distortion.
- HIP treatment can significantly enhance final material properties.
- CNC machining provides dimensional accuracy and surface finish.
How to Choose a Metal Material for 3D Printing
Follow these guidelines for selecting an optimal metal material:
- Match the alloy properties to design requirements like strength, hardness, thermal resistance etc.
- Consider post-processing needs – some alloys like Inconel are challenging to machine.
- Evaluate part size and geometry – some metals like aluminum are better for larger parts.
- Assess production volumes – prototype in cheaper material then switch to higher performance alloys.
- Account for material availability and costs early in the design stage.
- Work closely with your 3D printing service provider to select the best material.
- Optimize print parameters like orientation and layer thickness based on the specific alloy chosen.
- Perform test builds and material characterization tests before starting production.
常见问题
Q: Which metal alloy has the highest strength for 3D printing?
A: Inconel superalloys like Inconel 718 have the highest tensile strength but are less ductile. Titanium Ti-6Al-4V has the highest strength-to-weight ratio.
Q: Are parts 3D printed in stainless steel corrosion resistant?
A: Yes, 316L and other stainless steel alloys maintain their excellent corrosion resistance after 3D printing.
Q: What is the most commonly used titanium alloy in 3D printing?
A: Ti-6Al-4V is the most popular titanium alloy, comprising 90% of all titanium 3D printing. It offers the best all-round properties.
Q: Which aluminum alloy is best for 3D printing?
A: 6061 and 7075 are most widely used, with 6061 offering good corrosion resistance at lower cost, and 7075 chosen for high-strength structural applications.
Q: Are post-processing steps mandatory for metal 3D printed parts?
A: Post-processing like support removal, stress relieving and surface finishing is highly recommended for optimal material properties and performance.
Q: Which 3D printing process works with the widest range of metal alloys?
A: Binder jetting and directed energy deposition can work with most alloys but powder bed fusion produces higher resolution parts.
Q: How does part accuracy compare between machining and 3D printing of metals?
A: CNC machined parts allow tighter tolerances and better surface finish than 3D printed metals. However, 3D printing enables more complex geometries.
Q: Which metal 3D printing process has the fastest build speeds?
A: Binder jetting can achieve the highest print speeds, building parts up to 10 times faster than powder bed fusion processes.
