共查询到18条相似文献,搜索用时 46 毫秒
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在粉末材料爆炸压实试验中,爆轰压力是一个重要的工艺参数.本文结合质量不变条件、粉末材料泊松比与相对密度之间的关系、粉末材料的屈服准则以及粉末材料塑性变形时应力应变关系,研究爆炸压实工艺中爆轰压力与粉末致密度之间的关系,以便为实际的爆炸压实试验选择爆轰压力时提供理论依据.结果表明,随着爆轰压力增加,粉末爆炸压实坯的致密度也增加;当采用与其屈服强度相等的爆轰压力时,只能获得80.4%理论密度的棒坯;只有采用16倍屈服应力的爆轰压力时,爆炸压实才有可能获得99%理论密度的棒坯;无论爆轰压力多么大,爆炸压实法也不能得到完全致密的棒坯. 相似文献
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ITO纳米粉末爆炸压实烧结致密化陶瓷靶材研究 总被引:6,自引:0,他引:6
对ITO商业复合粉末应用爆炸冲击方法压实烧结,并对样品进行了XRD和ESM检测.通过粉末和压实后样品的XRD图及SEM照片的比较,发现在爆炸冲击压实纳米ITO陶瓷粉末时,能够使晶粒度减小,有助于后续烧结密实过程中控制ITO靶材的晶粒度的过分长大;SEM图片显示,在1200℃烧结的靶材微观结构比较均匀.本文探索了纳米ITO粉末冲击压实烧结的微观机理,并与以往人们对粉末的冲击沉能结论进行了比较,得出结论:压实烧结的主要机理是破碎填充效应,使得一部分粉末颗粒表面原子间的距离达到了点阵量级,从而产生键合力;一部分表面原子间的距离达到了一定小的程度,Vander Waals力使其结合. 相似文献
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The aim of present investigation is to gain deeper understanding of breakdown behavior and inter-particle bonding by conducting experimental tests. This may lead to improve the state of compaction by relative arrangement of initial parameters to maintain uniform distribution of current density and producing compacts with sufficient mechanical strength. Experimental work was carried out using two different set-ups. The first arrangement was employed to provide steady-state alternating voltage. The effect of column geometry and particle size on breakdown voltage was investigated under this condition. The second set-up, capacitor discharge circuit, was used to provide impulse voltage. Under this condition, the influence of column geometry, particle size, application of axial pressure, evacuation of air, energy input, electrode material and configuration on breakdown voltage was studied. Also, scanning electron microscopy was employed to study the effect of different parameters on inter-particle bonding. The results of experiments conducted on the influence of each of the voltage and capacitance on the compaction properties are also discussed. 相似文献
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文章总结了山西省十几条乳化炸药和粉状乳化炸药生产线的生产运行状况,并对其安全生产和技术管理进行了展望。 相似文献
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Experiments were carried out with different apparatus to compact electrolytic copper powders at distinct loading speeds. It appears that green densities of compacts prepared by HVC out-number that by conventional compaction by one percent. Compacts by quasi-static compaction are almost as dense as those by HVC under comparable peak pressure. The relationship between green compact density and peak pressure accords with Hang Pei-yun formula well. Spring-backs of HVC compacts are far smaller than those of conventional compaction and quasi-static compaction. HVC compacts are harder than compacts by conventional compaction and quasi-static compaction when they have the same density. 相似文献
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P. K. Rajagopalan S. V. Desai R. S. Kalghatgi T. S. Krishnan D. K. Bose 《Materials Science and Engineering: A》2000,280(2)
Consolidation and densification of metal powder are usually attained by compaction followed by prolonged high-temperature sintering or by hot pressing. However, these methods are not suitable where grain growth is to be avoided. So electric discharge compaction is being studied so as to establish a fast, cheap, and reproducible process. In this process, high current pulse for a few millisecond duration is passed through metal powder compacts held under pressure in a die. This paper gives the details of the investigation being carried out to establish the process parameters for the densification of titanium, tin and zinc powders. Remarkable improvements in the density and microstructure are noticed after subjection to the electric discharge. 相似文献
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为了研究聚合物基熔铸炸药与传统结晶型熔铸载体炸药装药工艺性能的差异,采用载体微观凝固形态检测、熔铸炸药流变性能测试、X光缺陷检测、凝固过程中温度 时间变化曲线检测、药屑状态观测等方法,对聚合物基熔铸炸药与传统结晶型2,4-二硝基苯甲醚(DNAN)基、3,4-二硝基呋咱基氧化呋咱(DNTF)基熔铸载体炸药的微观凝固特征、流动性能、缺陷分布、凝固过程释热、药面处理方式进行了研究。结果表明,聚合物基熔铸炸药载体凝固过程中未出现明显的固液结晶面;随着固体质量分数的提高,炸药流动性降低,但3种炸药均具有满足装药需要的流动性;DNAN基、DNTF基熔铸炸药凝固缺陷呈现不规则、缩孔深的凝固补缩特点,聚合物基熔铸炸药凝固收缩则体现出小幅度、集中、规则的收缩塌陷特点;DNAN基、DNTF基熔铸炸药凝固过程中存在过冷及结晶潜热释放现象,聚合物基熔铸炸药凝固不存在过冷和结晶潜热释放,且装药中心达到同一温度的时间明显短,有利于装药效率的提高;3种配方均具有良好的机械、热和静电安全性;聚合物基熔铸炸药呈现出良好的塑性,后处理比DNAN基、DNTF基熔铸炸药更容易。通过综合分析,聚合物基熔铸炸药综合装药工艺性能优于传统结晶型熔铸炸药。 相似文献