Jia Jianping, Hei Xiaoxuan, Yang Xiao, Zhao Wei, Wang Yuqi, Zhuo Qing, Li Yuanyuan, Dong Hangyu, Liu Futian, Li Yingru, Yan Xiaoshan
Faculty of Science, Yibin University, Yibin 644007, China.
School of Materials Science and Engineering, University of Jinan, Jinan 250024, China.
Materials (Basel). 2024 Apr 25;17(9):1992. doi: 10.3390/ma17091992.
A novel DC-assisted fast hot-pressing (FHP) powder sintering technique was utilized to prepare Al/Diamond composites. Three series of orthogonal experiments were designed and conducted to explore the effects of sintering temperature, sintering pressure, and holding time on the thermal conductivity (TC) and sintering mechanism of an Al-50Diamond composite. Improper sintering temperatures dramatically degraded the TC, as relatively low temperatures (≤520 °C) led to the retention of a large number of pores, while higher temperatures (≥600 °C) caused unavoidable debonding cracks. Excessive pressure (≥100 MPa) induced lattice distortion and the accumulation of dislocations, whereas a prolonged holding time (≥20 min) would most likely cause the Al phase to aggregate into clusters due to surface tension. The optimal process parameters for the preparation of Al-50diamond composites by the FHP method were 560 °C-80 MPa-10 min, corresponding to a density and TC of 3.09 g cm and 527.8 W m K, respectively. Structural defects such as pores, dislocations, debonding cracks, and agglomerations within the composite strongly enhance the interfacial thermal resistance (ITR), thereby deteriorating TC performance. Considering the ITR of the binary solid-phase composite, the Hasselman-Johnson model can more accurately predict the TC of Al-50diamond composites for FHP technology under an optimal process with a 3.4% error rate (509.6 W m K to 527.8 W m K). The theoretical thermal conductivity of the binary composites estimated by data modeling (Hasselman-Johnson Model, etc.) matches well with the actual thermal conductivity of the sintered samples using the FHP method.
采用一种新型的直流辅助快速热压（FHP）粉末烧结技术制备了铝/金刚石复合材料。设计并进行了三组正交实验，以探究烧结温度、烧结压力和保温时间对Al-50金刚石复合材料热导率（TC）和烧结机理的影响。不合适的烧结温度会显著降低热导率，因为相对较低的温度（≤520°C）会导致大量孔隙的保留，而较高的温度（≥600°C）会导致不可避免的脱粘裂纹。过大的压力（≥100MPa）会引起晶格畸变和位错的积累，而延长的保温时间（≥20min）很可能会由于表面张力导致铝相聚集形成团簇。通过FHP方法制备Al-50金刚石复合材料的最佳工艺参数为560°C-80MPa-10min，对应的密度和热导率分别为3.09g/cm³和527.8W/(m·K)。复合材料内部的孔隙、位错、脱粘裂纹和团聚等结构缺陷会强烈增强界面热阻（ITR），从而降低热导率性能。考虑到二元固相复合材料的ITR，Hasselman-Johnson模型能够更准确地预测在最佳工艺下FHP技术制备的Al-50金刚石复合材料的热导率，误差率为3.4%（509.6W/(m·K)至527.8W/(m·K)）。通过数据建模（如Hasselman-Johnson模型等）估算的二元复合材料的理论热导率与使用FHP方法烧结样品的实际热导率匹配良好。
