摘要：
Abstract: Al2O3 particle reinforced Ti2AlN matrix composites were prepared by vacuum hot pressing in situ forming Al2O3. The microstructure of the hot-pressed composite was analyzed by metallographic microscope, scanning electron microscope and transmission electron microscope. The phase composition of the hot-pressed composite was analyzed by x-ray diffraction (XRD). The composites mainly consist of thermodynamically stable α-Al2O3 phase and Ti2AlN phase. The Al2O3 particles are dispersed in the continuous Ti2AlN matrix. The volume fraction of Al2O3 phase is 40% ± 5%. The Al2O3 particles that the size is between 500 nm and 2 μm with an average of about 1 μm are equiaxed. The grain of Ti2AlN phase is disc-like, its thickness is about 100 nm, its length is between 0.5 and 2 μm, and its average geometric size is about 0.3 μm.#@#@#摘要: 采用真空热压法原位形成强化相Al2O3，制备出Al2O3颗粒增强Ti2AlN基复合材料。本文采用金相显微镜，扫描电镜，透射电镜分析了热压态复合材料的微观组织，采用x-射线衍射分析(XRD)分析了热压态复合材料的相组成。制备的Al2O3/Ti2AlN复合材料由热力学稳定的α-Al2O3相和Ti2AlN相组成，其中Al2O3颗粒弥散分布在连续的Ti2AlN基体里。Al2O3相的体积分数为40% ± 5%，呈等轴状，颗粒尺寸分布在500 nm~2 μm之间，平均为1 μm左右。Ti2AlN相晶粒为盘状，厚度大约是100 nm，长度在0.5~2 μm之间，平均几何尺寸0.3 μm左右。
摘要：
LEDs (Light Emitting Diodes) Light source due to conform to the low carbon, green and environmental protection and social development requirements, has been widely used in the field of information field, lighting, display, is the incandescent lamp, fluorescent lamp, gas discharge lamp after a new type of Light source. Many research institutions have developed with high level of LED testing equipment, but overall, the high cost of the equipment. At present, our country's national standards in the field of LED and related products is still a blank, no unified standards and test methods to regulate the industry, making the industry products are good and bad are intermingled. In the design of test system, this paper first introduces the basic theory about LED photometric measurement and measurement standards and the status quo at home and abroad, and the main optical parameters of traditional measurement methods are summarized. Then, according to the principle of digital imaging, the overall scheme of the two kinds of measurement system is presented. Therefore, this article USES the by a CCD camera and a lambert scattering screen composition, light from the LED light to the front of the screen surface, and CCD camera filmed illuminated screen. Experiment, he measured data for the system parameters in a calibration scheme. Since then, we can use two other LED light intensity distribution measurement system plan, this completes the LED the design and development of the spatial light intensity distribution measuring device, the set of instrument system can complete the LED light intensity and photometric parameters of rapid measurement, suitable for LED production testing and research.
摘要：
This experiment mainly study the influence of the thermal fatigue of solder joint, solder was - Cu and Sn, Pb, Sn - Ag is 760 microns in diameter, welding plate of 560 microns. Internationally accepted tin-lead solder is most likely to replace the Sn Ag - Cu alloy series. In order to study the temperature and stress under the dual function of single substrate BGA solder joint in the process of thermal fatigue deformation process, organizational structure evolution, establishing the model of fatigue study solder joint fatigue mechanism; Find out fast cyclic heating and fast cooling the coupling mechanism of solder joint fatigue and solder joint interface evolution process. First of all, experimental apparatus mainly has a high frequency current box, catheter, relay and thermocouple. Under the condition of rapid heating and rapid cooling, the thermal fatigue behavior of single substrate.
摘要：
BGA micro-joint with double substrates used by SAC305 lead-free solder is fabricated by reflowing process based on substrate FR-4. The microstructures of the solder joints are studied through the method of rapid thermal cycling (RPC). The double-based plate Cu/SAC305/Cu solder joint was tested at extreme temperature 60-180 degrees C by rapid thermal cycling 48 hours and 72 hours respectively, it was found the IMC grow by the zigzag shape, and fatigue cracks greatly appear at the interface of IMC/Cu, they are initiating and propagating along the boundary, and thread through the cross section of solder joint in the end, which lead to the failure of solder joint.
摘要：
The objective of this paper is to investigate the effect of rapid thermal cycling on microstructure and optical property (luminous flux and luminous efficiency) of high power light emitting diode (LED) by thermal fatigue testing from -40 to 125. Under an application of thermal fatigue device as a heating source, the specimens that were being non-operating and thermal fatigue testing in the experiment were rapidly heated and cooled based on a control system that employs a fuzzy logic algorithm, respectively. The optical performances, including luminous flux, luminous efficiency, radiant power and color temperature (CCT) of LED specimens were tested and analyzed. It was found that the rapid thermal cycling have similar evident influence on them. The results showed that the color purity of LED was also descended, the correlated color temperature (CCT) was also risen, but their changing rate and extents are different. The high and low temperature distribution in LED chip was simulated by finite element modeling which is helpful for the failure analysis and design of the reliability of the LED packaging. The microstructures of LED chips are analyzed after different rapid thermal cycling time. The results are showed that rapid thermal cycling can affect greatly the LED properties and interface microstructures. All the results indicate that this approach to rapid thermal cycling by using rapid heating source is feasible to investigate the optical performance of high power LED, so it can also effectively verify the reliability of LED devices.
摘要：
The objective of this paper is to investigate the effect of rapid thermal cycling on microstructure and optical property (luminous flux and luminous efficiency) of high power light emitting diode (LED) by thermal fatigue testing from -40 to 125. Under an application of thermal fatigue device as a heating source, the specimens that were being non-operating and thermal fatigue testing in the experiment were rapidly heated and cooled based on a control system that employs a fuzzy logic algorithm, respectively. The optical performances, including luminous flux, luminous efficiency, radiant power and color temperature (CCT) of LED specimens were tested and analyzed. It was found that the rapid thermal cycling have similar evident influence on them. The results showed that the color purity of LED was also descended, the correlated color temperature (CCT) was also risen, but their changing rate and extents are different. The high and low temperature distribution in LED chip was simulated by finite element modeling which is helpful for the failure analysis and design of the reliability of the LED packaging. The microstructures of LED chips are analyzed after different rapid thermal cycling time. The results are showed that rapid thermal cycling can affect greatly the LED properties and interface microstructures. All the results indicate that this approach to rapid thermal cycling by using rapid heating source is feasible to investigate the optical performance of high power LED, so it can also effectively verify the reliability of LED devices.
摘要：
The objective of this paper is to investigate the effect of rapid thermal cycling on microstructure and optical property (luminous flux and luminous efficiency) of high power light emitting diode (LED) by thermal fatigue testing from -40 to 125. Under an application of thermal fatigue device as a heating source, the specimens that were being non-operating and thermal fatigue testing in the experiment were rapidly heated and cooled based on a control system that employs a fuzzy logic algorithm, respectively. The optical performances, including luminous flux, luminous efficiency, radiant power and color temperature (CCT) of LED specimens were tested and analyzed. It was found that the rapid thermal cycling have similar evident influence on them. The results showed that the color purity of LED was also descended, the correlated color temperature (CCT) was also risen, but their changing rate and extents are different. The high and low temperature distribution in LED chip was simulated by finite element modeling which is helpful for the failure analysis and design of the reliability of the LED packaging. The microstructures of LED chips are analyzed after different rapid thermal cycling time. The results are showed that rapid thermal cycling can affect greatly the LED properties and interface microstructures. All the results indicate that this approach to rapid thermal cycling by using rapid heating source is feasible to investigate the optical performance of high power LED, so it can also effectively verify the reliability of LED devices.
摘要：
Lead-free solder has been widely used in electronic packaging products in printed circuit boards (PCB). Because soldering in the microelectronics industry not only provides the electronic connection, but also ensures the mechanical reliability of solder joints under the complex service conditions. This study provides some prospective into the microstructural changes of the solder joints interconnection by rapid thermal cycles. The goal of this paper is to investigate the thermal fatigue behavior of a single Sn-3.0Ag-0.5Cu (SAC) lead-free solder joint treated by rapidly alternating heating and cooling cycles. The microstructure and morphology of the interface between the solder ball and Cu substrate was observed using scanning electron microscopy (SEM). The intermetallic compounds (IMC) and the solder bump surface were analyzed by energy dispersive X-ray (EDX) and respectively. The experimental results showed that rapid thermal cycling had an evident influence on the interfacial microstructure of a single solder joint. The experiment revealed that microcracks initiate at the bottom of the SAC solder joint. In addition, rimous cracks initiated and propagated on the superficial oxide of the solder bump after rapid thermal cycling. The temperature distribution can be explained by finite element modeling (FEM) according to heat deformation theory in materials physics and based on metal thermal fatigue mechanism.
