（1. State Key Laboratory for Mechanical Behavior of Materials, Xian Jiaotong University, Xian 710049, China） (2. School of Materials Science and Engineering, Xian University of Technology, Xian 710048, China) (3. Jinduicheng Molybdenum Group Co,LTD，Xian 710077, China)
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DOI:
10.7502/j.issn.1674-3962.2016.03.06
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Abstract:
The hightemperature stability and mechanical properties of refractory molybdenum alloys are highly desirable for a wide range of critical applications. But molybdenum (Mo) alloys are also a wellknown example of bodycenteredcubic materials that suffer from low ductility and limited formability. In this paper, we firstly discuss the microstructureproperty relationships in traditional oxide dispersionstrengthened Mo alloys and analyze the fracture mechanisms. Based on these understandings, we propose a new nanostructuring strategy to solve the longstanding lowductility problem by optimizing the distribution of the grains, strengthening dispersions and solutes. In particular, a simple and costeffective molecularlevel liquidliquid mixing/doping technique is developed to achieve ultrafine submicronsized grains with nanosized oxide particles uniformly distributed in the grain interior. The resulting nanostructured Mo alloys boast not only a high yield strength of over 800 MPa but at the same time an extraordinary tensile elongation as large as ~40% at room temperature, which is increased by about 15% and above 160%, respectively, when compared with the ODS Mo alloys prepared by conventional methods. The new processing route can be readily adapted for largescale industrial productions of ductile Moalloys that can be extensively processed and shaped, including deep drawing, at low temperatures. Our findings represent a pathway towards engineering dispersionstrengthened materials with simultaneously high strength and ductility, a combination beyond conventional trends and expectations, which should be applicable to refractory metals such as tungsten.