Rephrasing Aging behaviour of 17-4 Essay Example | Topics and Well Written Essays - 750 words

Rephrasing Aging behaviour of 17-4 - Essay Example Continuously, layers of powder are deposited in a repeated cycle until the desired 3D structure is produced . DMLS process ensures production of parts that are fully dense and that require minimal post-processing activity. The DMLS process compares to another AM process popularly known as the Selective Laser Sintering (SLS). Conceptually, both SLS and DMLS are similar however, DMLS uses uncoated pre-alloyed metal powders for the sintering material, unlike SLS which utilizes coated metal powders or polymers . The final outcome of the DMLS procedure is characterized by fine or metastable microstructures , which at times may differ with the set international standards of conventional manufacturing. Moreover, further investigation into the mechanical properties of the microstructures resulting from the DMLS process is necessary to ensure that the structures produced are compatible and able to support the practical use they are intended. During the DMLS process, yielding begins at low values of about 600 Mpa due to the complexity of the process which results from the multiple constituents and interactions of the microstructure formation, especially precipitations. During the process, the structures may have large hardenings which may elicit discrepancies on the part of micro hardness and yield stress as a result of the strain induced transformation of the austenite. The austenite transformation occurs when the whole or part of the plastic field and the accumulation of twins is retained. The low twining probability in austenite may be attributed to the rapid nucleation of the martensite plates within the high twinned austenitic regions, which causes continuous strain-induced transformation along the plastic field. In addition, the accumulation of twins in the martensite affects the plastic flow providing increase in strain hardening ability . The presence of retained austenite material may significantly influence the mechanical composition