高性能钼合金的微观组织设计制备与性能优化  

Microstructural Design and Property Optimization of Mo Alloys with High Performance

作　　者：刘刚[1] 张国君[1,2] 江峰[1] 丁向东[1] 孙院军[3] 王林[3] 罗建海[3] 孙军[1] 

机构地区：[1]西安交通大学金属材料强度国家重点实验室,陕西西安710049 [2]西安理工大学材料科学与工程学院,陕西西安710048 [3]金堆城钼业集团有限公司,陕西西安710077

出　　处：《中国材料进展》2016年第3期205-211,232,共7页Materials China

基　　金：国家"863"重点项目(2008AA031000);国家自然科学基金(51321003;51371141;51322104);国家科技支撑计划(2012BAE06B02)

摘　　要：传统方法制备的稀土氧化物弥散强化钼合金(ODS钼合金)强度有限且塑性较差,导致其变形深加工能力不足,严重制约了其工业应用。分析了ODS钼合金制备工艺-微观组织-力学性能之间的因果关系,提出了钼合金纳米掺杂强韧化的新思路,即纳米尺度稀土氧化物颗粒均匀弥散分布在细晶钼基体晶粒内部、同时部分颗粒分布在晶界上的多层级微观结构优化原则,发展了制备该类新型钼合金的液液掺杂方法,所得到的高性能钼合金在拉伸屈服强度达到800 MPa量时,拉伸延伸率仍近40%,与传统方法制备的ODS钼合金相比,屈服强度提高了约15%,拉伸延伸率提高了逾160%,实现了强度和延性的同步提升。进一步建立了强韧化理论模型,对强度和延性的改善进行了量化描述。这种高性能钼合金由于力学性能优异、加工性能好,已获得了工业应用,其微观组织调控原则以及制备方法对其它难熔金属结构材料的高性能化同样具有借鉴意义。The high-temperature 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 well-known example of body-centered-cubic materials that suffer from low ductility and limited formability. In this paper, we firstly discuss the microstructure-property re- lationships in traditional oxide dispersion-strengthened Mo alloys and analyze the fracture mechanisms. Based on these under- standings, we propose a new nanostructuring strategy to solve the long-standing low-ductility problem by optimizing the distri- bution of the grains, strengthening dispersions and solutes. In particular, a simple and cost-effective molecular-level liquid- liquid mixing/doping technique is developed to achieve ultrafine submicron-sized grains with nanosized oxide particles uni- formly 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 large-scale industrial productions of ductile Moalloys that can be ex-tensively processed and shaped, including deep drawing, at low temperatures. Our findings represent a pathway towards engineering dispersion-strengthened materials with simultane- ously high strength and ductility, a combination beyond con- ventional trends and expectations, which should be applicable to refractory metals such as tungsten.

关 键 词：钼合金 强韧化 纳米稀土氧化物 液液掺杂 多层级微观结构 高延性 

分 类 号：TG146.3[一般工业技术—材料科学与工程]