Effect of solid solution plus double aging on microstructural characterization of 7075 Al alloys fabricated by selective laser melting (SLM)
•7075 Al alloy fabricated by SLM was treated by a novel solid solution plus aging.•Microstructural changes of alloys before and after heat treatment were analyzed.•Effect of microstructures and precipitates on hardness of alloys was analyzed. The microstructure, hardness and phase transformation of...
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Veröffentlicht in: | Optics and laser technology 2019-06, Vol.114, p.158-163 |
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Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | •7075 Al alloy fabricated by SLM was treated by a novel solid solution plus aging.•Microstructural changes of alloys before and after heat treatment were analyzed.•Effect of microstructures and precipitates on hardness of alloys was analyzed.
The microstructure, hardness and phase transformation of 7075 aluminum alloy fabricated by selective laser melting (SLM) under solid solution plus double aging were studied by using optical microscope (OM), microhardness tester, scanning electron microscope (SEM) and transmission electron microscope (TEM). The test results show that microstructures of as-received alloy present the obvious uneven inter-channel structure. When the solid solution plus double aging were used, the alloy shows the homogeneous refinement structure. The inter-channel structure of the alloy completely disappeared. The hardness under the solid solution plus double aging also increased compared with the as-received alloy (HV80), and the average hardness is about HV158. Some typical S phase (Al2CuMg) and θ phase (Al2Cu) precipitated at the grain boundary, which has a significant effect to improve the hardness of alloys via the dispersion strengthening and precipitation strengthening. |
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ISSN: | 0030-3992 1879-2545 |
DOI: | 10.1016/j.optlastec.2019.02.006 |