Metals, technical ceramics and high-performance polymers: the material drives the process, not the other way round. These are the materials we work with, with the properties that matter and the industrial applications of each.
The correct sequence is always the same: first the component's functional requirement — temperature, load, chemical environment, contact with a patient or with food — then the material that satisfies it, and only at the end the process able to shape that material. Reversing the order is the most common and the most expensive mistake.
Among metals the field is wide: nickel superalloys for heat, maraging and tool steels for moulds, stainless for corrosion and hygiene, titanium for strength-to-weight and biocompatibility, aluminium for light weight and conductivity, copper for heat, cobalt-chrome for wear.
In technical ceramics the choice runs through the split between oxides — alumina, zirconia, mullite, cordierite — and non-oxides: silicon carbide, silicon nitride, aluminium nitride, boron nitride, boron carbide. These families behave in opposite ways on thermal shock, conductivity and toughness.
Among polymers the dividing line is continuous service temperature: below 100 °C polyamides are enough, above 200 °C you need PEEK, PEKK and polyetherimides.
Start from the worst condition the part has to survive in service, not the nominal one: peak temperature, cyclic load, chemical environment, sector regulation. It is the only figure that is not negotiable.
Every material is available on a limited set of processes, and each leaves a signature: anisotropy, residual porosity, internal stress, sintering shrinkage. The finished part does not have handbook properties.
Stress relief, solution annealing, ageing, HIP, grinding: a material only reaches its stated performance after the right treatment, and the supply chain has to be qualified before the design is set.
Six families, from turbine superalloys to mould steel. For each alloy: the properties that drive the choice and the sectors where it is used.
The most widely used superalloy in additive: precipitation hardened, it combines high strength, weldability and dimensional stability up to about 650 °C.
Outstanding marine and chemical corrosion resistance with a very forgiving printing window; lower mechanical strength than 718.
Very high temperature oxidation resistance with good formability: the classic material of the combustion section.
Hot-section alloys whose aluminium and titanium content makes them hard to weld: they need dedicated parameters and heat treatment.
The standard for printed mould inserts: it builds without cracking, machines in the annealed state and hardens by ageing with minimal distortion.
Hot-work tool steel: it withstands thermal fatigue and prolonged contact with molten alloy, where maraging would lose hardness.
High-speed steel hot hardness and wear resistance, now also obtainable by binder jetting and sintering.
Austenitic, ductile and biocompatible: the reference for chemical, food and medical use, with excellent weldability and no quench hardening.
Precipitation-hardening stainless: near alloy-steel strength without giving up corrosion resistance.
Austenitic-ferritic structure: roughly twice the yield strength of 316L and better resistance to chloride stress corrosion.
The most used titanium alloy in the world. Grade 23 ELI, with extra-low interstitials, is the implant-grade version.
Unalloyed titanium: more ductile and more corrosion resistant, mechanically weaker. For when the environment matters more than the load.
The reference alloy for aluminium additive: easy to print, light and a good thermal conductor.
Scandium refines the grain and pushes specific strength well beyond casting alloys: developed for lightweight structures.
Aluminium-copper for service temperatures above Al-Si alloys, at the cost of a narrower process window.
Hardness, wear resistance and biocompatibility in one material, with good high-temperature behaviour as well.
Copper alloyed with chromium and zirconium: near pure-copper conductivity with usable strength, printable with infrared lasers.
Maximum electrical and thermal conductivity; it reflects infrared laser light, so reliable printing needs green or blue sources.
Tantalum for biocompatibility and chemical inertness, tungsten for density, melting point and radiation shielding.
| Material | Density | Indicative service | Typical strength | Chosen for |
|---|---|---|---|---|
| Inconel 718 | 8.2 | ≤ ~650 °C | Rm 1,100–1,400 MPa | Hot strength |
| Hastelloy X | 8.2 | ≤ ~1,100 °C | Rm 700–900 MPa | Extreme oxidation |
| Maraging 300 | 8.1 | ≤ ~400 °C | 50–54 HRC | Moulds and tooling |
| 316L | 8.0 | ≤ ~550 °C | Rm 500–650 MPa | Corrosion and hygiene |
| 17-4 PH | 7.8 | ≤ ~300 °C | Rm 900–1,300 MPa | Strength + corrosion |
| Ti6Al4V | 4.4 | ≤ ~400 °C | Rm 900–1,100 MPa | Weight and biocompatibility |
| AlSi10Mg | 2.67 | ≤ ~200 °C | Rm 350–450 MPa | Light weight and heat |
| Al-Mg-Sc | 2.67 | ≤ ~250 °C | Rm 480–530 MPa | Specific strength |
| CuCrZr | 8.9 | ≤ ~450 °C | ~300–320 W/m·K | Conductivity |
| CoCrMo | 8.3 | ≤ ~600 °C | Rm 900–1,200 MPa | Wear and implants |
All figures on this page are indicative orders of magnitude, useful to steer a decision. The real properties of a component depend on the process, build orientation, heat treatment and supplier: before putting a number on a drawing, always check the datasheet for the specific alloy and process.
A nozzle working at 400 °C, one at 900 °C and one in contact with abrasive powder are the same component only on the drawing. The first is made in stainless, the second in Hastelloy or Inconel, the third in boron carbide or silicon carbide — and each of the three imposes a different process and supply chain.
That is why materials advice that does not engage with the real operating conditions is worth nothing: anyone can find the catalogue, not everyone asks the right question.
Oxides, non-oxides and bioceramics. The difference between families is not one of degree: these materials behave in opposite ways on thermal shock, conductivity and toughness.
The world's most used technical ceramic: hard, insulating, chemically inert, with a performance-to-price ratio nothing else matches.
The toughest of the ceramics: phase transformation arrests the crack, so it resists impact and bending while staying hard.
Blends of the two above: the ratio is chosen to move the trade-off between alumina hardness and zirconia toughness.
Silicates with very low thermal expansion: they take severe thermal cycling and shock better than any dense oxide.
Near-zero thermal expansion and collapsibility after casting: the classic material for investment casting cores.
Hardness close to diamond, high thermal conductivity and stability at temperatures where any superalloy has already failed.
The best combination of toughness, thermal shock resistance and low density among non-oxides: the bearing ceramic.
Conducts heat almost like a metal and insulates like a ceramic: the reason dense power electronics is possible at all.
High-temperature solid lubricant, machinable with standard tools and not wetted by molten metals. The cubic form, c-BN, is an extreme abrasive instead.
Among the hardest materials known, very light and a strong neutron absorber: a combination with no alternative.
Carbides bonded by a metallic phase: not pure ceramics, but they occupy the same application space in extreme wear, with more toughness.
Calcium phosphates with the same chemistry as the mineral phase of bone: osteoconductive and, in the case of TCP, resorbed as tissue grows back.
The same structural ceramics in controlled purity and grain size versions, with documented long-term clinical history.
From powder-bed polyamides to engineering ketones, through to photopolymer resins for tooling and medical use.
The workhorse of powder bed fusion: functional parts without supports, good mechanical and chemical resistance. PA11 is bio-based and tougher.
Glass, carbon or aluminium filled for stiffness and dimensional stability, paid for with reduced toughness.
Printable elastomer: perceived hardness is designed through lattice geometry, not only through the compound.
Chemical resistance, weldability and low density: the polymer of containers and fluid circuits, with shrinkage to manage in printing.
The benchmark engineering thermoplastic: continuous service around 250 °C, resistance to chemicals, radiation and repeated sterilisation.
A PEEK relative with slower crystallisation and a wider process window: easier to handle on large parts and thick layers.
Thermoplastic with fire, smoke and toxicity certification: the reason it is found in aircraft interiors.
Repeated autoclave sterilisation, transparency or strong chemical resistance, at a lower cost than the ketones.
Finish and detail superior to any extrusion or sintering technology, with thermoset behaviour.
Formulations with certified biocompatibility for patient contact, from models to temporary-use devices.
Models that burn out without residue for investment casting, and photopolymer elastomers for seals and soft prototypes.
Start from the functional requirement in the worst operating condition — peak temperature, load, chemical environment, applicable regulation — identify the materials that satisfy it, and only then look at which processes can shape those materials at the required volume. Starting from the available technology instead of the requirement is the most expensive mistake, because it means redesigning everything when the part fails in the field.
718 is precipitation hardened and far stronger mechanically, but stable only to around 650 °C: above that, the precipitates that strengthen it dissolve. 625 is weaker and not precipitation hardened, but it handles oxidation and corrosion at higher temperature and is more forgiving to print. In short: 718 where the load matters, 625 where the environment does.
When the part is going to be printed. Maraging 1.2709 builds without cracking, machines in the annealed state and hardens by low-temperature ageing with minimal distortion: that combination is what makes conformal cooling inserts possible. Where the part is machined from solid and works hot for long periods, H13 remains the better choice because it holds hardness at higher temperature.
Alumina when you need electrical insulation, chemical inertness and hardness at contained cost — it is the starting choice in most cases. Zirconia when the part takes impact or bending: it is far tougher thanks to phase transformation, but costs more, weighs more, and has to be assessed against hydrothermal ageing in hot water. ZTA and ATZ blends exist precisely to shift that trade-off.
In several cases yes, and the advantage is not only weight: PEEK does not corrode, insulates electrically, damps vibration and can be sterilised. The limits are stiffness far below steel, creep under sustained load and poorer dimensional stability with humidity. Replacement works when the section is redesigned, not when the metal geometry is copied into polymer.
No, and assuming they are is a recurring mistake. An additive part has anisotropic properties — different along the build axis than in the plane — may carry residual porosity, and starts life with internal stresses that need relieving. With correct heat treatment, and HIP where appropriate, many alloys match or exceed wrought values, but that is a result to be verified with witness specimens built in the same job, not taken for granted.
Tell us how the part works — temperature, loads, environment, volumes — and we will tell you which materials actually hold up and with which process they are made.
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