In this work,we used the selective laser melting(SLM)fabricated Co-Cr alloy with prominent residual strain,extremely non-equilibrium microstructures,and low stacking fault energy as a precursor to fabricate materials ...In this work,we used the selective laser melting(SLM)fabricated Co-Cr alloy with prominent residual strain,extremely non-equilibrium microstructures,and low stacking fault energy as a precursor to fabricate materials with the optimal grain boundary character distribution.The grain boundary engineering(GBE)of the Co-Cr alloy was achieved by a simple heat treatment of the SLM-fabricated Co-Cr alloy.The obtained GBE Co-Cr alloy exhibited 81.47%of special grain boundaries(∑3^(n)n=1,2,3),while it substantially disrupted the connectivity of the random high-angle boundaries,successfully reducing the propensity of intergranular degradation.Slow strain rate tests(SSRTs)showed that the GBE Co-Cr alloy possessed lower stress corrosion cracking(SCC)susceptibility and higher ductility in the corrosive environment(0.9%Na Cl solution)than in the air.The high fraction of special boundaries,coupled with the stress-induced martensitic transformation(SIMT)in the GBE Co-Cr alloy yielded these results,which unique and rarely simultaneously satisfied for common structural materials.The current"SLM induced GBE strategy"offers a novel approach towards customized GBE materials with high SCC resistance and ductility in the corrosive environment,shedding new light on developing high-performance structural materials.展开更多
基金supported by Chengdu Major Science and Technology Innovation Projects(2019-YF08-00221-GX)。
文摘In this work,we used the selective laser melting(SLM)fabricated Co-Cr alloy with prominent residual strain,extremely non-equilibrium microstructures,and low stacking fault energy as a precursor to fabricate materials with the optimal grain boundary character distribution.The grain boundary engineering(GBE)of the Co-Cr alloy was achieved by a simple heat treatment of the SLM-fabricated Co-Cr alloy.The obtained GBE Co-Cr alloy exhibited 81.47%of special grain boundaries(∑3^(n)n=1,2,3),while it substantially disrupted the connectivity of the random high-angle boundaries,successfully reducing the propensity of intergranular degradation.Slow strain rate tests(SSRTs)showed that the GBE Co-Cr alloy possessed lower stress corrosion cracking(SCC)susceptibility and higher ductility in the corrosive environment(0.9%Na Cl solution)than in the air.The high fraction of special boundaries,coupled with the stress-induced martensitic transformation(SIMT)in the GBE Co-Cr alloy yielded these results,which unique and rarely simultaneously satisfied for common structural materials.The current"SLM induced GBE strategy"offers a novel approach towards customized GBE materials with high SCC resistance and ductility in the corrosive environment,shedding new light on developing high-performance structural materials.
