Facility for preparation of advanced metallic and ceramic materials

先进金属和陶瓷材料制备装置

• 批准号: 389742-2010
• 负责人: Plucknett, Kevin
• 金额: $ 7.15万
• 依托单位: Dalhousie University
• 依托单位国家: 加拿大
• 项目类别: Research Tools and Instruments - Category 1 (<$150,000)
• 财政年份: 2009
• 资助国家: 加拿大
• 起止时间: 2009-01-01 至 2010-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=443005
• 关键词: Facility; preparation; advanced; metallic; ceramic

While advanced ceramics and their composites have been prepared from powders for many decades, there is now a growing interest in producing metallic components from powder sources. This approach offers the benefit of near-net shape production and reduced material wastage, when compared to more conventional metal forming routes such as casting. The processing of advanced particulate materials requires that the powders are initially consolidated into the desired shape, prior to final densification by sintering. Occasionally this can be achieved through simple uniaxial compression, especially for selected metallic alloys such as aluminium and steels (using pressures up to 600 MPa), and when the particle sizes are moderately coarse (i.e. > 40 microns). However, for metals such as magnesium and titanium, which can deform by twinning, die binding becomes a serious problem even at moderate uniaxial pressures (i.e. > 100 MPa). In addition, the use of fine metallic powders (i.e. < 20 microns) is simply not feasible, even though such powders would have potentially greater 'sinterability'. Similarly, for micron or sub-micron sized ceramic powders it is generally necessary to use high pressure isostatic compaction. Uniaxially pressed ceramic preforms do not have sufficient green strength or density, as they invariably cannot be pressed at pressures above ~50 MPa, as die binding and wear can arise. These problems can be alleviated by cold isostatic pressing (CIP), especially when following low pressure uniaxial pressing. The present proposal requests the provision of funding for a CIP system, capable of pressures up to 689 MPa, which will be used for alloys based on aluminium, magnesium, nickel and titanium, as well as for advanced structural ceramics, such as silicon nitride and titanium carbide. The CIP will allow production of novel, ceramic-reinforced metal matrix composites, where fine particle sizes can be used to promote microstructural homogeneity. An atmosphere controlled glove-box is also available, so that more reactive metal powders can be pressed without exposure to an oxidising atmosphere, which is a major problem for finer particle sizes. Finally, precision CNC milling facilities are available for further shaping of CIPed preforms.

虽然先进的陶瓷及其复合材料已经用粉末制备了几十年，但现在人们对用粉末生产金属部件的兴趣越来越大。与传统的金属成形方法（如铸造）相比，这种方法具有近净形状生产和减少材料浪费的优点。高级颗粒材料的加工要求粉末在烧结最终致密化之前，首先被固化成所需的形状。有时，这可以通过简单的单轴压缩来实现，特别是对于选定的金属合金，如铝和钢（使用压力高达600 MPa），当颗粒尺寸中等粗糙（即bbb40微米）。然而，对于像镁和钛这样的金属，它们可以通过孪生变形，即使在中等单轴压力（即> 100 MPa）下，模具结合也会成为一个严重的问题。此外，使用细金属粉末（即< 20微米）是不可行的，即使这种粉末可能具有更大的“烧结性”。同样，对于微米或亚微米尺寸的陶瓷粉末，通常需要使用高压等静压实。单轴压制的陶瓷预制体没有足够的生坯强度或密度，因为它们总是不能在高于~ 50mpa的压力下压制，因为会产生模具粘合和磨损。这些问题可以通过冷等静压（CIP）来缓解，特别是在低压单轴压后。目前的提案要求为压力可达689兆帕的CIP系统提供资金，该系统将用于铝、镁、镍和钛基合金以及先进结构陶瓷，如氮化硅和碳化钛。CIP将允许生产新型陶瓷增强金属基复合材料，其中细粒度可用于促进微观结构的均匀性。气氛控制手套箱也是可用的，这样就可以在不暴露于氧化气氛的情况下压制更多的活性金属粉末，这是细颗粒尺寸的主要问题。最后，精密数控铣削设备可用于进一步成形CIPed预制件。