In this work,a near-beta Ti-5Al-5Mo-5V-1Cr-1Fe titanium alloy was fabricated by selective laser melting(SLM),and the microstructure evolution together with the mechanical properties was studied.The as-fabricated alloy...In this work,a near-beta Ti-5Al-5Mo-5V-1Cr-1Fe titanium alloy was fabricated by selective laser melting(SLM),and the microstructure evolution together with the mechanical properties was studied.The as-fabricated alloy showed columnarβgrains spreading over multiple layers and paralleling to the building direction.The distinct microstructure of as-fabricated alloy was composed of near-β(more than 98.1%)with a submicron cellular structure.Different SLM processing parameters such as hatch spacing could affect the microstructure of as-fabricated alloy,which could thus further significantly affect the mechanical properties of as-fabricated alloy.In addition,the as-fabricated alloy with the distinct microstructure exhibits yield strength of 818 MPa combined with elongation of more than 19%,which shows that SLM is a potential technology for manufacturing near-beta titanium components.展开更多
The mechanical properties of many materials prepared by additive manufacturing technology have been greatly improved.High strength is attributed to grain refinement,formation of high density dislocation and existence ...The mechanical properties of many materials prepared by additive manufacturing technology have been greatly improved.High strength is attributed to grain refinement,formation of high density dislocation and existence of cellular structures with nanoscale during manufacturing.In addition,the super-saturated solid solution of elements in the matrix and the solid solution segregation along the wall of the cellular structures also promote the improvement of strength by enhancing dislocation pinning.Hence,the existence of cellular structure in grains leads to differences in the prediction of material strength by Hall-Petch relationship,and there is no unified calculation method to determine the d value as grain size or cell size.In this work,representative materials including austenite 316L SS were printed by selective laser melting(SLM),and the strength was predicted.The values of cell size and grain size were substituted into Hall-Petch formula,and the results showed that the calculation error for 316L is increased from 4.1%to 11.9%.Therefore,it is concluded that the strength predicted by grain size is more accurate than that predicted by cell size in additive manufacturing materials.When calculating the yield strength of laser additive manufacturing metal materials through the Hall-Petch formula,the grain size should be used as the basis for calculation.展开更多
基金Project(2019B010943001)supported by Key-area Research and Development Program of Guangdong Province,ChinaProject(2020)supported by the Fund of State Key Laboratory of Powder Metallurgy,Central South University,China。
文摘In this work,a near-beta Ti-5Al-5Mo-5V-1Cr-1Fe titanium alloy was fabricated by selective laser melting(SLM),and the microstructure evolution together with the mechanical properties was studied.The as-fabricated alloy showed columnarβgrains spreading over multiple layers and paralleling to the building direction.The distinct microstructure of as-fabricated alloy was composed of near-β(more than 98.1%)with a submicron cellular structure.Different SLM processing parameters such as hatch spacing could affect the microstructure of as-fabricated alloy,which could thus further significantly affect the mechanical properties of as-fabricated alloy.In addition,the as-fabricated alloy with the distinct microstructure exhibits yield strength of 818 MPa combined with elongation of more than 19%,which shows that SLM is a potential technology for manufacturing near-beta titanium components.
基金Projects(51505166,51871249)supported by the National Natural Science Foundation of ChinaProject(Guike AB19050002)supported by the Guangxi Key Research and Development Program,China+1 种基金Project(2020JJ2046)supported by the Hunan Science Fund for Distinguished Young Scholars,ChinaProject(2020WK2027)supported by the Hunan Key R&D Plan,China。
文摘The mechanical properties of many materials prepared by additive manufacturing technology have been greatly improved.High strength is attributed to grain refinement,formation of high density dislocation and existence of cellular structures with nanoscale during manufacturing.In addition,the super-saturated solid solution of elements in the matrix and the solid solution segregation along the wall of the cellular structures also promote the improvement of strength by enhancing dislocation pinning.Hence,the existence of cellular structure in grains leads to differences in the prediction of material strength by Hall-Petch relationship,and there is no unified calculation method to determine the d value as grain size or cell size.In this work,representative materials including austenite 316L SS were printed by selective laser melting(SLM),and the strength was predicted.The values of cell size and grain size were substituted into Hall-Petch formula,and the results showed that the calculation error for 316L is increased from 4.1%to 11.9%.Therefore,it is concluded that the strength predicted by grain size is more accurate than that predicted by cell size in additive manufacturing materials.When calculating the yield strength of laser additive manufacturing metal materials through the Hall-Petch formula,the grain size should be used as the basis for calculation.
