Study on Wear Properties of Cryogenic Treated Additive Manufactured SLS Components

This study examines the influence of cryogenic treatment on the microstructure and on the physical properties of the rapid prototype SLS material. The wear properties of the rapid prototype SLS material both before and after cryogenic treatment are studied in three phases. Phase I deals with the sample preparation through the SLS technique; Phase II involves the preliminary tests like roughness test, hardness test, SEM and wear test. Phase III is the cryogenic treatment of the sample in the setup designed. The cryogenic coolant used is Nitrogen, having a boiling point of 77 K, and the whole treatment process takes about 2 to 3 days. Phase IV deals with the testing of the cryogenically treated samples in which similar tests to that in Phase I are carried out. These results are tabulated and graphs are plotted. Furthermore, the percentage change in the hardness and wear properties of the samples are found. The cryogenic aging of the material and the effect of controlled ramp up/ramp down on the samples in the cryogenic treatment is also discussed in detail in this study. It was observed that the wear resistance of the SLS component has increased significantly after the cryogenic treatment. This was mainly due to the transformation of austenite into martensite which increases hardness of the component.