原材料粉末对氮化硅陶瓷球性能的影响

分别采用国产和进口氮化硅原材料粉末制备不同规格的氮化硅陶瓷球,研究原材料粉末对氮化硅陶瓷材料力学性能、烧结致密化、组织结构和陶瓷球表面质量的影响。结果表明:随着氮化硅陶瓷球尺寸增大,原材料粉末对陶瓷球质量影响增大;对于大尺寸陶瓷球,使用进口原材料粉末能明显提高材料的力学性能、组织均匀性,能够促进烧结致密化,提高陶瓷球表面质量。

选区激光熔化金属增材制造实验质量控制

金属增材制造是一项战略性智能制造前沿技术,具有传统制造工艺不可比拟的巨大优势,在众多高技术领域有着广阔的应用前景。但是金属增材制造工艺复杂,制造过程中的各个环节都会直接影响到最终结果的质量和可靠性。为了提高和保证金属增材制造科研实验质量,基于选区激光熔化(SLM)技术工艺原理及流程,进行了金属增材制造实验质量控制探究。结合最新发布的相关国家标准以及实践经验,建立了实用的标准化SLM实验流程及操作规范。同时,通过分析影响SLM金属增材制造实验质量的主要因素,构建了关键因素的质量控制方法,从而为实现金属增材制造实验质量的有效控制及提升提供重要保障。

Hot compressive deformation behavior of an in-situ TiB whisker reinforced Ti matrix composite

An in-situ TiB whisker reinforced Ti matrix (TiBw/Ti) composite is fabricated by powder metallurgy technique followed by hot extrusion. Hot compressive deformation behavior of the composite, in which the TiB whiskers were oriented along the extruded direction, is investigated. The results indicate that the hot compressive resistance of the TiBw/Ti composite is higher than that of the unreinforced Ti, and hot compressive resistance of the composite in the direction parallel to the whisker orientation is higher than that in the direction perpendicular to the whisker orientation. The hot compressive resistance of the composite increases with increasing strain rate and decreasing temperature. With increasing test temperature, the rate of the decrement of the compressive flow stress of the composite is higher than that of the unreinforced Ti. With increasing amount of compressive deformation, more and more TiB whiskers rotate and break during deformation. The rotation of the whiskers is easier at higher temperature, while, at lower temperature it becomes more difficult and whisker breakage becomes much more serious.