I just published an article on the Accendo Reliability website about the approaches for evaluating the reliability of the materials used in a product. Any product is an assembly of components comprised of different materials. The reliability of the product depends on the reliability of the materials – their ability to withstand exposure to the use conditions without degrading to the point that the component or joint stops performing as needed.
There are two approaches for evaluating the reliability of materials: 1) product testing and 2) materials testing. Both involve exposing test samples to actual or simulated use conditions and evaluating the response of the test samples as a function of the amount of exposure to the test conditions. Unfortunately, many design teams do not use materials reliability testing as a way to gather data and improve the likelihood of passing product testing.
The article discusses the differences between both approaches and their advantages and disadvantages.
Here's the link to the article - Reliability Testing - Product vs. Materials.