7A04铝合金超厚板的淬透性

采用万能力学试验机、光学显微镜、扫描电镜等手段,研究了7A04铝合金超厚板的显微组织、性能及淬透性。结果表明:225 mm厚的7A04铝合金热轧板材经过475 ℃×340 min的固溶淬火处理后,再进行120 ℃×24 h 时效,其表面的力学性能最好,抗拉强度为584 MPa,屈服强度为500 MPa,伸长率为11%;T/4厚度层力学性能最差,抗拉强度为396 MPa,屈服强度为257 MPa,伸长率为11%,强度与表面分别相差32%、49%。淬透深度为单面32 mm。通过调控化学成分、加大轧制压下量、增加淬火冷却速率等可改善板材表心力学性能之差,并提高淬透性。     

大型结构构件地震作用模拟装置MUST的研发及加载控制验证

地震作用下结构柱在水平向变形的同时也承受较大的轴力,故在结构柱的地震作用模拟试验中需考虑轴向力的影响,特别是变轴力。常用的轴向力加载方法有铰接轴向作动器加载法,高强钢棒后张法以及滑动支座加载法等,但这些传统的加载方式均存在对试件施加的侧向力不能直接测得,需根据加载方法进行相应修正的问题。通过研发的多功能结构加载(multiple usage structural test,MUST)系统,侧向力和轴向力加载可相互独立,测得的侧向力和轴向力即为施加至模型试件的实际荷载而无需修正,改善了传统加载系统的不足。在样机HNU-MUST上进行了空载试验、大型钢管柱拟静力试验和拟动力试验,验证了MUST加载系统的可行性和准确性。     

新型储粮保护剂甲嘧硫磷防治储粮害虫的应用试验

本试验使用浙江省宁波化工研究所合成生产的50%甲嘧硫磷乳油.以单独拌合(载体全拌和喷洒全拌)小麦和玉米的方法,以及粮面拌合与低剂量磷化铝(1克/米~3)熏蒸配合处理小麦的方法,进行了小型生产性试验.所用剂量处理玉米为5、10、15ppm; 处理小麦分别为5、10ppm.试验结果表明,5ppm剂量的载体拌粮和直接喷粮,对最初含0～2头/公斤害虫的小麦和玉米,能保持在一年内不发生虫害.以低剂量磷化铝熏蒸粮堆配合甲嘧硫磷喷洒粮面,也同样有效地控制了主要害虫在一年内不发生感染.处理后粮食中的药剂残留量比联合国粮农组织和世界卫生组织农药残留联席会议推荐的最高残留极限(MRL)10mg/kg低20～50%,而且对小麦的发芽率无不良影响.使用该药单独拌粮防虫费用,比防虫磷单独拌粮费用减少16%,比磷化铝常规熏蒸费减少83%.     

7075铝合金轧制板MgO缺陷的形成原因及其预防措施

使用超声波检测设备对轧制前后的7075铝合金进行探伤,通过光学显微镜、扫描电子显微镜和能谱仪对缺陷进行分析。分析结果显示缺陷为MgO夹杂。铸锭超声波检测符合ASTM B594-2019标准A级质量要求,但是铸锭轧制成板材并固溶淬火后质量不合格,说明这种缺陷经热加工后超声当量增加。Mg是易氧化元素,在铝合金的熔炼和铸造过程中,高温铝液表面与空气接触发生氧化反应形成MgO,并在铸造过程中进入铸锭形成MgO夹杂。铸造时应采取控制搅拌力度,提高铸造温度,控制Ar-Cl_2混合气体注入量和使用过滤装置等预防措施来避免MgO夹杂的出现。     

Electrochemical performance of Gd-Co-Mn alloys

The Gd-Co-Mn alloys with compositions of Gd33.3Co66.7,Gd33.3Mn66.7,Gd22.2Co74.8Mn3 and Gd25Co70Mn5 were prepared and examined by X-ray diffractometer.The electrochemical properties of these alloys such as discharge capacity,cycling performance and high rate dischargeability were investigated by battery testing instruments in alkaline electrolyte.The discharge capacity of Gd22.2Co74.8Mn3 was the highest among these alloys at the same discharge current density,and the maximum value was 376.7 mAh/g discharged at 150 mA/g.The discharge capacities of the alloys Gd33.3Co66.7 and Gd33.3Mn66.7 reached their maxima(about 225 and 325 mAh/g)at discharge current density of 150 mA/g.A comparison of the electrochemical performance of the Gd-Co-Mn alloys revealed that the alloy Gd22.2Co74.8Mn3 possessed better electrochemical performance and had better discharge capacity,cycle stability,while the alloy Gd25Co70Mn5 had a better high rate discharge ability.In general,the electrochemical performance of ternary alloys was better than binary alloys in this case.     

抽筒子疲劳裂纹扩展研究及剩余寿命预测

针对炮闩机构的抽筒子爪部出现疲劳断裂的问题,研究抽筒子的疲劳裂纹扩展及剩余寿命预测。针对抽筒子材料45CrNiMoVA,开展室温下断裂韧度和疲劳裂纹扩展试验,测试材料的断裂韧度,结合实验数据拟合得到Paris断裂公式。通过对抽筒子裂纹扩展因素的研究得到:应力由300 MPa减小至200 MPa时,剩余寿命增幅最大,增大约3.2倍;初始裂纹长度从0.5 mm增大到1 mm时;剩余寿命减小幅度最大,减小约1.8倍;当材料的断裂韧度越大,剩余寿命越大,且增长的趋势越来越缓慢。     

7A09铝合金热精轧板热处理工艺研究

通过拉伸试验、显微组织、扫描电镜及差热扫描量热分析等手段,研究固溶处理制度对7A09铝合金热精轧板组织及性能的影响。结果表明,7A09铝合金板材经过470℃1 h+482℃1 h+490℃20 min强化固溶处理,然后进行120℃24 h时效后,其横向抗拉强度为607 N/mm~2,屈服强度为517 N/mm~2,伸长率为15.3%,且合金中S(Al2Cu Mg)相回溶。     

Isothermal section of Nd-Zr-Si ternary system at 773 K

Phase diagram is an important basis for materials research and materials application.The phase relations of the Nd-Zr-Si ternary system at 773 K were investigated by X-ray powder diffraction analysis,metallographic analysis and scanning electron microscopy with en-ergy dispersive analysis.The isothermal section of the phase diagram of the Nd-Zr-Si ternary system at 773 K was determined.The isother-mal section of the system consisted of 13 single-phase regions,23 two-phase regions and 11 three-phase regions.The homogeneity range of α-NdSix was from 63 at.% to 66 at.% Si(with x=1.70-1.94).The maximum solid solubilities of Nd in Zr-Si binary compounds and Zr in the Nd-Si binary compounds were observed less than 1 at.% at 773 K.     

2.1GHz CMOS低噪声放大器

采用上海华虹NEC0.35μm标准CMOS工艺进行RFCMOS窄带低噪声放大器的设计和制作。测试结果表明,在2.1GHz时,输入驻波比1.1,输出驻波比1.5,增益18dB,噪声系数2.7dB,P-1dB输出功率9dBm。