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A Critical Evaluation of the Processing and Properties of Ultrafine-Grained Materials Produced by Intense Plastic Straining

对强塑性应变生产的超细晶材料的加工和性能的严格评估

基本信息

批准号：
9625969
负责人：
Terence Langdon
金额：
$ 37.7万
依托单位：
University of Southern California
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
1996
资助国家：
美国
起止时间：
1996-08-01 至 2000-01-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=9625969&HistoricalAwards=false
关键词：
Critical Evaluation Processing Properties Ultrafine

项目摘要

9625969 Langdon This research investigates processing parameters and microstructural characteristics that are associated with ultrafine grained materials, including the influence of microstructure and concurrent microstructural evolution on the mechanical properties of materials at elevated temperatures. The research employs a new processing method equal channel angular pressing (ECA) to create nanocrystalline metal alloys. Past experiments have established that metallic alloys with ultrafine grain sizes in the nanometer range have the potential for high ductilities and superplastic-like flow at relatively low temperatures. The alloy grain boundaries are generally in a nonequilibrium condition and contain a large number of extrinsic dislocations. ECA provides a capability for producing intense plastic straining that can refine the metal alloy grain size into the nanometer range. Aluminum and aluminum-based alloys and copper alloys are selected for the study because this selection allows an evaluation of the role of stacking fault energy and its effects on dislocation networks and grain boundary structure. %%% The research could lead to a new processing technique for deformation processing of nanocrystalline materials and could impact future metal alloy processing in the metal forming industries. ***

9625969 Langdon 这项研究调查了与超细晶粒材料相关的加工参数和微观结构特征，包括微观结构和并发微观结构演化对材料在高温下机械性能的影响。该研究采用新的加工方法等通道角压制（ECA）来制造纳米晶金属合金。过去的实验已经证实，具有纳米范围超细晶粒尺寸的金属合金具有在相对较低的温度下具有高延展性和超塑性流动的潜力。合金晶界一般处于非平衡状态，含有大量外在位错。 ECA 具有产生强烈塑性应变的能力，可将金属合金晶粒尺寸细化至纳米范围。选择铝和铝基合金以及铜合金进行研究，因为这种选择可以评估堆垛层错能的作用及其对位错网络和晶界结构的影响。 %%% 这项研究可能会带来一种用于纳米晶材料变形加工的新加工技术，并可能影响金属成型行业未来的金属合金加工。 ***