We previously determined 'Tableting properties' by using a multi-functional single-punch tablet press(GTP-1). We proposed plotting 'Compactability' on the x-axis against'Manufacturability' on t...We previously determined 'Tableting properties' by using a multi-functional single-punch tablet press(GTP-1). We proposed plotting 'Compactability' on the x-axis against'Manufacturability' on the y-axis to allow visual evaluation of 'Tableting properties'. Various types of tableting failure occur in commercial drug production and are influenced by the amount of lubricant used and the shape of the punch. We used the GTP-1 to measure'Tableting properties' with different amounts of lubricant and compared the results with those of tableting on a commercial rotary tableting machine. Tablets compressed with a small amount of lubricant showed bad 'Manufacturability', leading to sticking of powder on punches.We also tested various punch shapes. The GTP-1 correctly predicted the actual tableting results for all punch shapes. With punches that were more likely to cause tableting failure, our system predicted the effects of lubricant quantity in the tablet formulation and the occurrence of sticking in the rotary tableting machine.展开更多
TiNi and Ti-based shape memory alloys were processed by equal channel angular pressing （ECAP） at 673-773 K along Bc route to obtain ultrafine grains for increasing the strength of parent phase and improving the func...TiNi and Ti-based shape memory alloys were processed by equal channel angular pressing （ECAP） at 673-773 K along Bc route to obtain ultrafine grains for increasing the strength of parent phase and improving the functional properties. The effects of both thermodynamically stable and metastable second phases on the mechanical properties and martensitic transformations of these alloys were investigated. It is found that thermodynamically stable Ti2Ni phase has no effect on martensitic transformation and superelasticity of Ti-rich TiNi alloy, thermodynamically stable α phase is harmful for ductility of Ti-Mo-Nb-V-Al alloy, but metastable Ti3Ni4 phase is effective for R phase transformation, martensitic transformation and superelasticity of Ni-rich TiNi alloy. The mechanisms of the second phases on the martensitic transformations and mechanical properties were discussed.展开更多
The evolution of Ti3Ni4 precipitates in Ti49.2Ni50.8 alloy during equal channel angular pressing(ECAP) and intermediate annealing was investigated by transmission electron microscopy. The solution-treated Ti49.2Ni50.8...The evolution of Ti3Ni4 precipitates in Ti49.2Ni50.8 alloy during equal channel angular pressing(ECAP) and intermediate annealing was investigated by transmission electron microscopy. The solution-treated Ti49.2Ni50.8 alloy was aged at 450 ℃ for 10 to 60 min to obtain Ti3Ni4 precipitates ranging from 37 to 75 nm. After ECAP at 450 ℃ for one pass, Ti3Ni4 precipitates introduced by aging for 10 and 30 min totally dissolve into the matrix;however, those produced by aging for 60 min become smaller. The critical size of Ti3Ni4 precipitates to totally dissolve into matrix is determined to be in the range of 37-68 nm. The dislocation density of ECAP-processed samples depends on the initial size of Ti3Ni4 precipitates after aging. With increasing the duration of initial aging from 10 to 60 min, the dislocation density firstly increases and then decreases.展开更多
Pure alumina ceramic tube and 95 alumina ceramic （the ceramic with 95.84% alumina） tube were prepared by using self-prepared alumina micrometer powder without agglomeration as raw material. The ceramic green was sha...Pure alumina ceramic tube and 95 alumina ceramic （the ceramic with 95.84% alumina） tube were prepared by using self-prepared alumina micrometer powder without agglomeration as raw material. The ceramic green was shaped by isostatic pressing and sintered at different temperature from 800 to 1 600 ℃ for 2 h. The 95 ceramic tube sintered at 1 550 ℃ for 2 h had mean particle size of 4 μm, bend strength of 437 MPa and volume density of 3.714 g/cm3. Shape memory effect during sintering was observed. XRD results showed that no phase transition occurred during shape memory process, which indicated that shape memory effect was not caused by phase transition. Several probable causes of the alumina ceramic shape memory effect were discussed in this paper.展开更多
In order to overcome the shortcomings of conventional hot pressing, a novel near net-shape technique, called radial hot pressing, for P/M parts with large height-to-diameter (H/D) ratio was introduced. Effects of proc...In order to overcome the shortcomings of conventional hot pressing, a novel near net-shape technique, called radial hot pressing, for P/M parts with large height-to-diameter (H/D) ratio was introduced. Effects of processing parameters on the microstructures and density of P/M TiAl base alloy valves were studied. Results show that the radial hot pressing is an effective technique for manufacturing valves with a H/D ratio of about 10:1, and the perfect joint interface between the Mo sheet and the parts is helpful for subsequent HIPing.展开更多
文摘We previously determined 'Tableting properties' by using a multi-functional single-punch tablet press(GTP-1). We proposed plotting 'Compactability' on the x-axis against'Manufacturability' on the y-axis to allow visual evaluation of 'Tableting properties'. Various types of tableting failure occur in commercial drug production and are influenced by the amount of lubricant used and the shape of the punch. We used the GTP-1 to measure'Tableting properties' with different amounts of lubricant and compared the results with those of tableting on a commercial rotary tableting machine. Tablets compressed with a small amount of lubricant showed bad 'Manufacturability', leading to sticking of powder on punches.We also tested various punch shapes. The GTP-1 correctly predicted the actual tableting results for all punch shapes. With punches that were more likely to cause tableting failure, our system predicted the effects of lubricant quantity in the tablet formulation and the occurrence of sticking in the rotary tableting machine.
基金Project (50671067) supported by the National Natural Science Foundation of ChinaProject (09JC1407200) supported by the Science and Technology Committee of Shanghai, China
文摘TiNi and Ti-based shape memory alloys were processed by equal channel angular pressing （ECAP） at 673-773 K along Bc route to obtain ultrafine grains for increasing the strength of parent phase and improving the functional properties. The effects of both thermodynamically stable and metastable second phases on the mechanical properties and martensitic transformations of these alloys were investigated. It is found that thermodynamically stable Ti2Ni phase has no effect on martensitic transformation and superelasticity of Ti-rich TiNi alloy, thermodynamically stable α phase is harmful for ductility of Ti-Mo-Nb-V-Al alloy, but metastable Ti3Ni4 phase is effective for R phase transformation, martensitic transformation and superelasticity of Ni-rich TiNi alloy. The mechanisms of the second phases on the martensitic transformations and mechanical properties were discussed.
文摘碳纤维混杂增强复合材料由于具有重量轻、可设计性强等诸多优点,广泛用于汽车、海洋、航空航天等行业.根据固化剂与环氧树脂的配比化学原理,计算出石墨烯-碳纤维混杂增强树脂基(GO-CF/EP)复合材料的最佳配比为1∶5,并采用真空浸渗热压成型工艺(VIHPS)制备1∶2~1∶7共六个配比的试样,结合形状记忆性能测试及微观形貌的观察,得到固化剂与环氧树脂实际最佳配比.实验结果表明,GO-CF/EP复合材料性能主要取决于体系中交联度的大小,交联度越大,复合材料的形状记忆性能越好,微观组织形貌也较理想.当基体配比为1∶5时,GO-CF/EP复合材料体系中交联度最大,微观形貌呈现均匀致密的状态,形状固定率最大,为95.90%;形状回复率最大,为95.40%;形状回复时间最短,为80.30 s;形状回复力最大,为9.48 N.当基体配比为1∶2或1∶7时,固化剂过量或不足,交联度较小,微观组织形貌中有大量的基体聚集区,其形状记忆性能下降,形状固定率及回复率也相应减小,分别为82.99%,81.66%,81.91%,78.75%;形状回复力分别只有5.20 N和5.50 N.
基金financial supports from the National Natural Science Foundation of China (51671064)the National Key R&D Program of China (2017YFE0123500)。
文摘The evolution of Ti3Ni4 precipitates in Ti49.2Ni50.8 alloy during equal channel angular pressing(ECAP) and intermediate annealing was investigated by transmission electron microscopy. The solution-treated Ti49.2Ni50.8 alloy was aged at 450 ℃ for 10 to 60 min to obtain Ti3Ni4 precipitates ranging from 37 to 75 nm. After ECAP at 450 ℃ for one pass, Ti3Ni4 precipitates introduced by aging for 10 and 30 min totally dissolve into the matrix;however, those produced by aging for 60 min become smaller. The critical size of Ti3Ni4 precipitates to totally dissolve into matrix is determined to be in the range of 37-68 nm. The dislocation density of ECAP-processed samples depends on the initial size of Ti3Ni4 precipitates after aging. With increasing the duration of initial aging from 10 to 60 min, the dislocation density firstly increases and then decreases.
基金Funded by the Natural Science Foundation of Guangxi University for Nationalities(Nos.200702YJ19 and 2008ZD011)National Natural Science Foundation of China(No.51172049)+2 种基金Special Prophase Project of 973 Program Research of China(No.2012CB722804)Guangxi Higher Education Institutes Talent Highland Innovation Team Scheme(No.GJR201147-12)Construction Project of Key Laboratory of Chemical and Biological Transformation Process of Guangxi Higher Education Institutes(No.GJKY20129)
文摘Pure alumina ceramic tube and 95 alumina ceramic （the ceramic with 95.84% alumina） tube were prepared by using self-prepared alumina micrometer powder without agglomeration as raw material. The ceramic green was shaped by isostatic pressing and sintered at different temperature from 800 to 1 600 ℃ for 2 h. The 95 ceramic tube sintered at 1 550 ℃ for 2 h had mean particle size of 4 μm, bend strength of 437 MPa and volume density of 3.714 g/cm3. Shape memory effect during sintering was observed. XRD results showed that no phase transition occurred during shape memory process, which indicated that shape memory effect was not caused by phase transition. Several probable causes of the alumina ceramic shape memory effect were discussed in this paper.
文摘In order to overcome the shortcomings of conventional hot pressing, a novel near net-shape technique, called radial hot pressing, for P/M parts with large height-to-diameter (H/D) ratio was introduced. Effects of processing parameters on the microstructures and density of P/M TiAl base alloy valves were studied. Results show that the radial hot pressing is an effective technique for manufacturing valves with a H/D ratio of about 10:1, and the perfect joint interface between the Mo sheet and the parts is helpful for subsequent HIPing.
