The twinning-induced plasticity(TWIP)effect has been widely utilized in austenite steels,β-Ti alloys,and recently developed face-centered-cubic(FCC)high-entropy alloys(HEAs)to simultaneously enhance the tensile stren...The twinning-induced plasticity(TWIP)effect has been widely utilized in austenite steels,β-Ti alloys,and recently developed face-centered-cubic(FCC)high-entropy alloys(HEAs)to simultaneously enhance the tensile strength and ductility.In this study,for the first time,the TWIP effect through hierarchical{332}<113>mechanical twinning has been successfully engineered into the TiZrHfNb refractory HEAs by decreasing temperature and tailoring the content of Nb to destabilize the BCC phase.At cryogenic tem-perature,the comprehensive hierarchical{332}<113>mechanical twins are activated in TiZrHfNb_(0.5) alloy from micro-to nanoscale and progressively segment the BCC grains into nano-scale islands during de-formation,ensuring sustainable strain hardening capability and eventually achieving a substantial 35%uniform tensile elongation.In addition,at 77 K,the tensile strength and uniform elongation of TiZrHfNbx alloys can further be adjusted by a moderate increase of Nb.The results above shed new light on the de-velopment of high-performance refractory HEAs with a high and adjustable strength and ductility com-bination down to the cryogenic temperature.展开更多
基金This work was supported by the National Natural Science Foun-dation of China(Nos.52301163 and 51821001)the National Key R&D Program of China(No.2022YFB3706800)+1 种基金P.K.Liaw very much appreciates the support from(1)the National Science Foun-dation(Nos.DMR-1611180,1809640,and 2226508)(2)the US Army Research Office(Nos.W911NF-13–1–0438 and W911NF-19–2–0049).
文摘The twinning-induced plasticity(TWIP)effect has been widely utilized in austenite steels,β-Ti alloys,and recently developed face-centered-cubic(FCC)high-entropy alloys(HEAs)to simultaneously enhance the tensile strength and ductility.In this study,for the first time,the TWIP effect through hierarchical{332}<113>mechanical twinning has been successfully engineered into the TiZrHfNb refractory HEAs by decreasing temperature and tailoring the content of Nb to destabilize the BCC phase.At cryogenic tem-perature,the comprehensive hierarchical{332}<113>mechanical twins are activated in TiZrHfNb_(0.5) alloy from micro-to nanoscale and progressively segment the BCC grains into nano-scale islands during de-formation,ensuring sustainable strain hardening capability and eventually achieving a substantial 35%uniform tensile elongation.In addition,at 77 K,the tensile strength and uniform elongation of TiZrHfNbx alloys can further be adjusted by a moderate increase of Nb.The results above shed new light on the de-velopment of high-performance refractory HEAs with a high and adjustable strength and ductility com-bination down to the cryogenic temperature.
