The aerospace and military sectors have widely used AA7075, a type of 7075 aluminum alloy, due to its exceptional mechanical performance. Selective laser melting (SLM) is a highly effective method for producing intric...The aerospace and military sectors have widely used AA7075, a type of 7075 aluminum alloy, due to its exceptional mechanical performance. Selective laser melting (SLM) is a highly effective method for producing intricate metallic components, particularly in the case of aluminum alloys like Al-Si-Mg. Nevertheless, the production of high-strength AA7075 by SLM is challenging because of its susceptibility to heat cracking and elemental vaporization. In this study, AA7075 powders were mechanically mixed with SiC and TiC particles. Subsequently, this new type of AA7075 powder was effectively utilized in green laser printing to create solid components with fine-grain strengthening microstructures consisting of equiaxial grains. These as-printed parts exhibit a tensile strength of up to 350 MPa and a ductility exceeding 2.1%. Hardness also increases with the increasing content of mixed powder, highlighting the essential role of SiC and TiC in SLM for improved hardness and tensile strength performance. .展开更多
利用Coats-Redfem动力学模型和热重质谱联用TG-MS研究了聚碳硅烷（PCS）/Ti体系的热裂解动力学行为。用X射线衍射和扫描电镜等技术研究了PCS/Ti体系热裂解过程特点和化学反应机理。结果表明,PCS/Ti体系的热解反应过程以一级热分解化学...利用Coats-Redfem动力学模型和热重质谱联用TG-MS研究了聚碳硅烷（PCS）/Ti体系的热裂解动力学行为。用X射线衍射和扫描电镜等技术研究了PCS/Ti体系热裂解过程特点和化学反应机理。结果表明,PCS/Ti体系的热解反应过程以一级热分解化学反应为主,可分为3个阶段,300～343℃,活化能227.08 k J·mol-1;343～511℃,活化能34.41 k J·mol^＋-1;511～645℃,活化能为15.76 k J·mol^＋-1。热解反应的表观活化能与热解温度有较大关系,随着反应的进行逐步减小。TG-MS分析表明：PCS热解挥发气体为H2和CH4以及C的碎片。扫描电镜和X射线分析结果表明：热解到1000℃有明显的Si C物相。金属Ti粉与部分C反应形成了Ti C,可获得Ti C/Si C复合陶瓷。展开更多
文摘The aerospace and military sectors have widely used AA7075, a type of 7075 aluminum alloy, due to its exceptional mechanical performance. Selective laser melting (SLM) is a highly effective method for producing intricate metallic components, particularly in the case of aluminum alloys like Al-Si-Mg. Nevertheless, the production of high-strength AA7075 by SLM is challenging because of its susceptibility to heat cracking and elemental vaporization. In this study, AA7075 powders were mechanically mixed with SiC and TiC particles. Subsequently, this new type of AA7075 powder was effectively utilized in green laser printing to create solid components with fine-grain strengthening microstructures consisting of equiaxial grains. These as-printed parts exhibit a tensile strength of up to 350 MPa and a ductility exceeding 2.1%. Hardness also increases with the increasing content of mixed powder, highlighting the essential role of SiC and TiC in SLM for improved hardness and tensile strength performance. .
文摘利用Coats-Redfem动力学模型和热重质谱联用TG-MS研究了聚碳硅烷（PCS）/Ti体系的热裂解动力学行为。用X射线衍射和扫描电镜等技术研究了PCS/Ti体系热裂解过程特点和化学反应机理。结果表明,PCS/Ti体系的热解反应过程以一级热分解化学反应为主,可分为3个阶段,300～343℃,活化能227.08 k J·mol-1;343～511℃,活化能34.41 k J·mol^＋-1;511～645℃,活化能为15.76 k J·mol^＋-1。热解反应的表观活化能与热解温度有较大关系,随着反应的进行逐步减小。TG-MS分析表明：PCS热解挥发气体为H2和CH4以及C的碎片。扫描电镜和X射线分析结果表明：热解到1000℃有明显的Si C物相。金属Ti粉与部分C反应形成了Ti C,可获得Ti C/Si C复合陶瓷。
