How to test the quality of a metal foam?
Metal foam is a product of modern structural materials research. It has been widely used in aerospace, petrochemical, environmental protection and other fields in this century due to its excellent sound insulation, heat insulation, gas permeability and excellent impact energy absorption performance. A car made of a metal foam material not only enhances the safety of the collision buffer, but also effectively reduces the weight of the car and improves fuel efficiency. The bullet-proof vests developed by the composite metal foam can be easily resisted by the special ceramic slabs, and the armor-piercing bullets with a speed of more than 3,000 kilometers per hour can be easily used. The armor of some warships is even made of foam metal materials, so the application prospect of the foam metal is self-evident.
Metal Foam are currently widely used in the main types of nickel foam, copper foam, aluminum foam and their alloys. They are mainly used to manufacture automobile bumpers, electromagnetic shields, fluid filters, electromechanical shock absorbers, and the like. Metal foam as an emerging material, its development space can be said to be limitless, so the research and testing of foam metal is particularly important. Among them, the mechanical properties of foam metal are the key to the performance of foam metal materials.
However, it may also be because the metal foam is an emerging industry, so the relevant national standard has not yet been introduced. The domestic standards for the detection of metal foam are currently only GB/T 20251-2006 "nickel foam for batteries" and JG/T 359-2012 "foam aluminum sheets for construction". The foreign standards are only ISO 13314 "Metal material ductility test metal foam compression test method", JIS H7902-2008 "Porous metal compression test method", DIN 50134-2008 "Metal material test, metal porous material compression test", etc. Relevant standards can be relied upon.
So, let's first take a look at the testing items for nickel foam and aluminum foam.
Metal foam nickel detection projects mainly include chemical composition (carbon, sulfur, iron, copper, silicon, phosphorus, nickel, cobalt) size and tolerance, mechanical properties (tensile strength, elongation after fracture, flexibility, no breaks) ), physical properties (area density, areal density tolerance, number of holes, allowable deviation of the number of holes, porosity), appearance quality, and the like.
Metal foam aluminum sheet testing items mainly include appearance, dimensional deviation, chemical composition, bulk density deviation, compressive strength, flexural strength, sound absorption coefficient, and combustion performance.
In fact, although there is no relevant national standard, but with reference to domestic and international standards, we can detect the density, pore size, pore size distribution, porosity, volume fraction, buckling strength, compressive strength, elastic deformation, elastic modulus and other indicators of metal foam. Through the analysis of these indicators, we can make a preliminary judgment on the overall quality performance of metal materials. Of course, better methods for detecting metal foams still hope that the state can issue relevant testing standards in time for regulation and guidance.