In order to reduce the junction temperature and improve the reliability of the high power single emitter semiconductor laser, the thermal resistor of chips with different cavity lengths was measured with the method of wavelength shift. Based on this, effect of cavity length on junction temperature and reliability of the single emitter laser was studied. The experiment results show that when the heat sink temperature is 20 ℃,the continuous waves output power is 10 W,the cavity length is 4 mm,and the minimum junction temperature of the device is 56. 3 ℃. When the heat sink temperature is 30 ℃,the cavity length is 4 mm,and the lowest degradation rate of the power is 3. 09% in 3 200 h life-test. Using the extrapolation method,the lifetime of the device is determined to be 20 711 h. And it is 3. 42 times of 2. 5 mm cavity length laser life time. This work demonstrates that the cavity length is a critical factor affecting the junction temperature and reliability of the device. In order to improve the lifetime,semiconductor lasers should choose the chips with long cavity length.

文章研究了LF5铝与A3钢摩擦挤压焊接工艺,该工艺已成功用于工业生产铝/钢电解电极.通过分析焊接工艺参数对LF5铝与A3钢接头金相组织、力学性能及导电性能的影响,获得了最佳的工艺参数.试验结果表明:摩擦挤压焊接形成的铝-钢接头的摩擦端面连接及螺纹挤压咬合连接提高了接头强度.通过该技术获得的焊接接头的导电性及力学性均能满足实际工业生产的要求.最优的摩擦挤压焊接参数是:旋转速度1 000 r/min,摩擦压力2.5 MPa,摩擦时间7 s,顶锻压力3.5 MPa,顶锻时间4 s.

Weld microstructure of 25% Cr super duplex stainless steel was investigated and the influence of alloy elements and welding procedure on weld microstructure was analysed.The results indicate that high chromium nickel equivalent ratio in the welds is needed for ideal microstructure,and for manual arc welding,heat input affects weld microstructure undistinguished while the annealing effect of the follow-up bead increases austenite content in preceding beads.

According to the physical dimension of the tool,a 3D finite element heat-transfer model of FSW was built on the basis of theoretical analysis of heat-transfer.With the finite element analysis software ANSYS and limited measured temperature data,red copper and brass FSW process thermal-structural coupled analysis was done.The results show that the heat source of 3 mm thick T2 and H62 sheetmetal FSW is the line heat source.The analogy model can be further simplified as 2D planar model.The temperature distribution around the tool reaches steady state in the intermediate stage of the welding.The variation tendency of equivalent stress and equivalent strain conforms with that of the temperature.On thickness direction,variations of stress and strain in different positions are consistent.

The aim of the present work is to discuss superplastic behavior of weld metal by executing high temperature tension test to weld metal of corrosion-resisting aluminium alloy and to find out the right parameters on which materials produce superplastic behavior and form fine joint. Experimental results show the maximal elongation percentage (91%) can be gotten on the condition of 450 degrees C and 0.6 mm/min collet travel speed. The m value, 0.534 can be calculated roughly from the stress-strain curve. It can be concluded superplastic behavior would appear around 450 degrees C.

The feasibility of friction stir welding of dissimilar materials of AZ31B magnesium alloy and LY12 aluminum alloy was investigated. The results show that it is possible to weld heterogeneous metals of AZ31B/LY12 when the right welding technology parameter is chosen, and basic sound apparent welded joints can be gotten. Meanwhile, the layer structure of magnesium alloy and the aluminum alloy piles into each other as mutual extrusion, and produce obvious distortion. The layer structure leads to the decline of mechanical properties compared with the base material in the weld zone.

The technology of friction-stir welding of dissimilar materials of T2 copper and AZ31B magnesium alloy was investigated, and by systematic measurement of the featured points during the friction stir welding T2 copper and AZ31B magnesium alloy , the regular pattern of heat cycle in FSW was basically known. The microstructure of the weld between plates was also analyzed. The present work showed that with the distance between welding seam and the featured points further, the maximum temperature tend to be lower, and the time of getting to the peak temperature tend to be later. The temperature gradient of the area around stirring shoulder was the highest. The joint microstructures and welding defects of friction stir welding T2 copper and AZ31B magnesium alloy was finally analyzed in the paper.

Compatible metallic cam and shaft made form 45 were connected by friction welding.The microstructure and properties in welded joint were analyzed and researched.Together with the reason of lower strength and fracture toughness were investigated to cam shaft made by heat forging.The excellences of the friction welding and joint formation were illustrated.The optimal welding and heat treatment parameters were afforded for friction welded joint.

新型的搅拌摩擦焊接工艺通常通过焊接参数的设置使材料达到塑性状态从而实现连接。而超塑性变形比塑性变形应力更低,变形量更大,更加有利于材料的加工。本文通过对防锈铝搅拌摩擦焊接头焊缝金属的高温拉伸试验,探讨了搅拌摩擦焊接头焊缝金属的超塑性行为,以期望选择合适的参数来使材料达到超塑性状态,形成良好的接头。试验结果表明:在450℃,夹头速度为0.6mm/min的情况下得到的最高延伸率为91%。从应力应变曲线初步计算得到m值为0.534。可以初步判定,在450℃附近,有超塑性现象。本研究的成果可应用于有色金属材料搅拌摩擦焊接参数的优化,深入研究其接头形成机理以及与其相关的技术理论,推动搅拌摩擦焊接技术的发展。

A heat transfer process determines the thermal cycles in a work piece during the friction stir welding(FSW) and affects its microstructure and mechanical properties.A good understanding of the heat transfer process in the work piece is helpful for predicting the residual stress in the welding work piece and the hardness in the weld zone.A three-dimensional heat transfer model based on the tool shape and size for FSW is established in this paper. With the Ansys finite element software and the temperature data at the limited number of measurement points,the temperature distribution and change of 6 mm thick purple copper friction stir welding were analyzed with finite elements.Heat transfer at the bottom surface of the work piece and the temperature-dependent thermal conductivity of the purple copper were considered during the calculation.The calculation results are in good agreement with the experimental results.

Incompatible metallic cut cutter made from 45 and W18Cr4V was connected by friction or flash welding.The microstructure and properties in welding joint were compared and analyzed.Together with the reason of lower strength and fracture toughness were investigated in the soldering seam zone of the flash welded joint.The excellences of the friction welding and joint formation were illustrated.The optimal welding parameters were given for friction welded joint.The results showed that friction welding of 45 and W18Cr4V cut cutter improved the microstructure and properties in soldering seam zone of welded joint.

According to the requirements of welding process for vortex type compressor of air conditioner manufactured in product line, a special girth welding machine with PLC as control core was developed, which had both upright and 45° incline service positions. And some key technologies were researched, such as structural design of machine body, reliable conduction of rotary weldments and quality control of welding process and so on. The experimental results showed that this machine could satisfy the requirements of welding quality and girth welding technology, results also proved the machine was a high-efficiency and low-cost automatic welding device.

The experimentation and research of AZ31B magnesium alloy friction stir welding were carried out by using plates of 5 mm in thickness.The results showed that the material suitable for the stir welding head was W6Mo5Cr4V2 high-speed steel.Its structure was in shape of concave round platform,the root of which was 5.5 mm in diameter,the butt 2.5 mm,the shoulder 12 mm,and its length was 4.7 mm.The tensile strength of magnesium alloy friction stir welding joint could be 90% of that of the parent metal,and the specific elongation could be 50% of that of the parent metal.The structure of the weld area was dynamic recrystallization.Apparent boundary existed between the weld area of the forward border joint and the parent metal,while trails of little molten showed in the transitional area of the back border.

国内的凸轮轴一般采用热锻工艺生产,但在生产中存在加热温度不易控制,组织易于过热甚至过烧,晶粒粗大,材料的强韧性较差,生产效率低,耗材、耗能大,生产成本高等缺点.而采用优质、高效、节能和无污染的摩擦焊接技术及焊后热处理工艺可以克服热锻工艺生产的缺点.

Friction welding weld ability test about titanium alloy TC4 (Ti-6Al-4V) was done in detail. Concerning the optimum selection of the parameters, the feature of the TC4 alloy friction welding process was discussed and the mechanical properties and structure of the joint was analyzed. The test result shows that TC4 alloy has good weld ability. Without particular protection step, a good welded joint can be obtained by means of optimum technological parameters. Because TC4 alloy has low heat conductivity, high heat plasticity and good anti oxidability, low welding parameters should be selected. The hardness in the welded area is a little lower than that in the matrix metal. The tension specimen was broken in the matrix metal. Fracture of tension and impact test show obviously tough fracture characteristic. Adopting the optimum parameters, the friction welded joint of TC4 alloy with equal strength and equal plasticity or even high strength and high plasticity can be prepared. The welded area of the joint presents densely woven and netted structures. The transitional zone between the welded area and the matrix metal presents double-stated structures.

The friction stir welding of red copper and brass were carried out at a serious of welding parameters. The properties and microstructures of the welded joints were analyzed. Tensile and bending test results indicate that the welded joints can achieve good combination of strength and ductility at rotation speed of 950rpm, welding speed of 60 mm/min and Z-axis force of 2000N. The tensile specimen failed at the base material of red copper. The weld nugget zone has very fine dynamic recrystallization microstructure and its Vickers hardness falls in between those of the two base metals. The sharp interface between the TMAZ and nugget might result in brittle fracture.

研究了电磁纯铁+不锈钢异种金属摩擦焊接头的成分、组织和性能以及对焊件轴向尺寸控制技术.结果表明,摩擦焊接头具有良好的组织和性能;隔磁体轴向尺寸偏差可以控制在±0.25mm.

Because of the differences of the physical and chemical performance of dissimilar materials, many difficulties exist when they are welded together with age-old welding ways. This paper studies the welding technology for L6-LY12, sets up correct welding technique and takes special measures, and monitors the metallographic organization and mechanics performance, therefore high quality welding joint is got. FSW joint with favorable mechanical property can be obtained by optimizing processing parameters.

Many results were obtained by plenty of quadrature-experiments on copperplate friction stir weld,which makes up of the training data of the ANN.The welding parameters(rotation speed,translation speed and pressure)were selected as the input and the tensile strength or the excellent of the joint (1represents a good joint and0represents a bad one)was selected as the output of the network.The network trained by the result of the quadrature-experiments with aberrated sample eliminated was used to estimate the quality of the joint.The friction stir welding ANN and user interface were established by MATLAB.It can be used to optimize the friction stir welding technical parameters.

搅拌摩擦焊(FSW)是近几年发展起来的新型摩擦焊接技术.铝合金搅拌摩擦焊接已成为国内外研究的热点,但对铜及其合金搅拌摩擦焊接的研究尚不多见.通过大量试验分析,优化了铜板搅拌摩擦焊接工艺.研究表明:工业纯铜具有良好的搅拌摩擦焊接性能,优化工艺可获得强度超过母材的搅拌摩擦焊接接头.