From the perspective of scientific exploration and development,modern industry demands structural materials that possess high strength,fracture toughness,and stiffness,while minimizing weight.Consequently,lightweight high-strength alloys such as titanium and aluminum,as well as load-bearing heat-resistant alloys like Ni-based superalloys,have become the focal point of new material research and development programs worldwide.Furthermore,these materials are also crucial for applications in laser additive manufacturing.

Advantages and differences between titanium alloy and aluminum alloy:

Titanium alloys and aluminum alloys are widely used in aerospace,automotive,and machinery manufacturing due to their excellent low density and structural strength.Especially in the aviation industry,they play a crucial role and are the main structural materials.Although titanium alloys are about two-thirds heavier than aluminum alloys,their inherent strength means that less material can be used to achieve the required strength.Titanium alloys,due to their strength and low density,are important materials for reducing fuel costs and are widely used in aircraft jet engines and various spacecraft.Aluminum alloys are currently the most widely used and common lightweight materials for automobiles,with a density only one-third that of steel.Studies have shown that up to 540kg of aluminum alloys can be used in a complete vehicle,which can reduce the vehicle's weight by 40%.Vehicles from brands such as Audi and Toyota,which adopt all-aluminum bodies,are good examples.

Since both materials possess high strength and low density,other factors must be considered when selecting an alloy.

In critical situations where high strength and low weight are required,every gram counts.However,if components of higher strength are needed,titanium is the best choice.Therefore,titanium alloys are used to manufacture medical devices/implants,complex satellite components,fixtures,and brackets.

In terms of cost,aluminum is the most cost-effective metal for machining or 3D printing;while titanium has a higher cost,the lightweight parts it produces will bring significant benefits in terms of fuel savings for aircraft or spacecraft,and titanium alloy parts have a longer service life.

In terms of thermal properties,aluminum alloy has high thermal conductivity and is often used to manufacture radiators;for high-temperature applications,titanium's high melting point makes it more suitable,and aero-engines contain a large number of titanium alloy components.

Titanium's corrosion resistance and low reactivity make it the most biocompatible metal,widely used in medical fields such as surgical instruments.Ti64 also exhibits excellent resistance to saline environments and is frequently used in marine applications.

In the aerospace industry,both aluminum alloys and titanium alloys are widely used.Titanium alloys,with their advantages of high strength and low density(only about 57%of steel),have a specific strength(strength/density)that far exceeds other metallic structural materials,enabling the production of components with high specific strength,good rigidity,and light weight.Titanium alloys are used in aircraft engine components,frames,skins,fasteners,landing gears,and more.Additionally,upon consulting relevant materials for 3D printing technology,it was found that aluminum alloys are suitable for working in environments below 200°C.The aluminum material used in the fuselage of the Airbus A380 accounts for more than one-third,and the C919 also extensively utilizes conventional high-performance aluminum alloy materials.Aluminum alloys are used in aircraft skins,bulkheads,wing ribs,and other parts.

Titanium alloys,due to their high melting point and difficult-to-process nature,are among the most costly metallic materials.However,Ti6Al4V titanium alloy has garnered significant attention in the aerospace industry due to its lightweight,high strength,and high temperature resistance characteristics.Its applications range from engine fans and compressor blades,disks,and casings working at low temperatures,with operating temperatures reaching up to 400-500°C.Additionally,it is also used in the manufacture of fuselages and space capsule components,rocket engine casings,and helicopter rotor hubs.However,due to titanium's poor electrical conductivity,it is not an ideal choice for electrical applications.Despite the relatively high price of titanium alloys,their high temperature resistance and corrosion resistance cannot be replaced by other lightweight metals.

Aluminum-based alloys possess excellent physical and mechanical properties such as low density,high specific strength,strong corrosion resistance,and good formability,making them widely used in industry.However,from the perspective of additive manufacturing processes,aluminum alloys have a relatively low density and poor powder flowability,leading to poor uniformity in powder placement on the powder bed during selective laser melting(SLM)or poor continuity in powder transport during laser metal deposition(LMD)processes.Therefore,high precision and accuracy are required for the powder spreading/feeding system in laser additive manufacturing equipment.

Currently,the aluminum alloys primarily used in additive manufacturing are Al-Si alloys,among which AlSi10Mg and AlSi12,which exhibit good fluidity,have been extensively researched.However,due to the fact that Al-Si alloys belong to the category of cast aluminum alloys,even with optimized laser additive manufacturing processes,their tensile strength still struggles to exceed 400MPa,limiting their application in load-bearing components with higher performance requirements in aerospace and other fields.

Modern aerospace components face a series of stringent requirements,including lightweight,high performance,high reliability,and low cost.The design and manufacturing of such complex structures are extremely challenging.By innovating and developing laser additive manufacturing technology for typical aerospace aluminum,titanium,and nickel-based components,we can not only achieve lightweight and high-performance materials selection,but also reflect the trend of precision and net shape forming in additive manufacturing technology.By realizing the integrated additive manufacturing of material-structure-performance,we can apply additive manufacturing technology to major projects in the aerospace field.