Titanium-based porous materials can be used in structural applications and medical implants because of their excellent mechanical properties at elevated temperatures, good corrosion resistance and wonderful biocompati...Titanium-based porous materials can be used in structural applications and medical implants because of their excellent mechanical properties at elevated temperatures, good corrosion resistance and wonderful biocompatibility. However, most of the methods used to produce the porous metal can only give limited porosity and uncontrollable pore morphologies. In the present study, a newly developed method of powder metallurgy using the space-holder technique was used to fabricate porous titanium with controllable porosity. The morphological features and mechanical properties of the products were fully investigated. The results show that the porosity is in the range of 55%-75%, and the mean pore size, with an average sphericity of -0.72, is 600 μm. The plateau stresses vary between 10 MPa and 35 MPa. As predicted by the Gibson-Ashby model, the plateau stress decreases with increasing porosity.展开更多
The infiltration casting fabrication process based on spherical CaCl_(2) space-holders and the compressive behavior including the mechanical performance and energy absorption capacity of open-cell aluminum foams were ...The infiltration casting fabrication process based on spherical CaCl_(2) space-holders and the compressive behavior including the mechanical performance and energy absorption capacity of open-cell aluminum foams were investigated.Open-cell aluminum foams with different porosities in the range of 63.1%to 87.3%can be fabricated by adjusting compression ratios of CaCl_(2) preforms prepared by precision hot-pressing.The compression tests show that a strain-hardening phenomenon always occurs especially for open-cell aluminum foam with low porosity,resulting in the inclining stress-strain curve in the plateau region.The energy absorption capacity of open-cell aluminum foam decreases with increasing porosity when compared at the same strain.However,when compared at a given stress,each foam can absorb the maximal energy among the five foams in a special stress range.Additionally,open-cell aluminum foam possesses the maximum energy absorption efficiency at its optimum operating stress.At this stress condition,the foam can absorb the highest energy compared with other foams at the same stress point.The optimum operating stress and the corresponding maximal energy absorption decrease with increasing the porosity.The optimum operating stress for energy absorption can also be determined similarly when taking into consideration of the lightweight extent of foams.展开更多
In the present work,a compressible and lubricating space-holder material commonly known as "acrawax" was used to process Cu foams with various pore sizes and various porosities.The foams were processed witho...In the present work,a compressible and lubricating space-holder material commonly known as "acrawax" was used to process Cu foams with various pore sizes and various porosities.The foams were processed without using binders to avoid contamination of their metal matrices.The lubricant space-holder material was found to facilitate more uniform flow and distribution of metal powder around the surface of the space holder.In addition,the use of acrawax as a space-holder material yielded considerably dense cell walls,which are an essential prerequisite for better material properties.The foams processed with a smaller-sized space holder were found to exhibit better electrical and mechanical properties than those processed with a coarser-sized space holder.The isotropic pore shape,uniform pore distribution throughout the metal matrix,and uniform cell wall thickness were found to enhance the properties pertaining to fine-pore foam samples.The processed foams exhibit properties similar to those of the foams processed through the lost-carbonate sintering process.展开更多
Titanium and its alloys are currently considered as one of the most important metallic materials used in the biomedical applications, due to their excellent mechanical properties and superior biocompatibility. In the ...Titanium and its alloys are currently considered as one of the most important metallic materials used in the biomedical applications, due to their excellent mechanical properties and superior biocompatibility. In the present study, a new effective method for fabricating high porosity titanium alloy scaffolds was developed. Porous Ti-6Al-4V scaffolds are successfully fabricated with porosities ranging from 30% to 70% using spaceholder and powder sintering technique. Based on its acceptable properties, spherical carbamide particles with different diameters （0.56, 0.8, and 1mm） were used as the space-holder material in the present investigation. The Ti-6Al-4V scaffolds porosity is characterized by using scanning electron microscopy. The results show that the scaffolds spherical-shaped pores are depending on the shape, size and distribution of the space-holder particles. This investigation shows that the present new manufacturing technique is promising to fabricate a controlled high porosity and high purity Ti-6Al-4V scaffolds for hard tissue replacement.展开更多
基金supported by the National Natural Science Foundation of China (No. 50504020)the Chongqing Natural Science Foundation, China (No. 2008BB4051)
文摘Titanium-based porous materials can be used in structural applications and medical implants because of their excellent mechanical properties at elevated temperatures, good corrosion resistance and wonderful biocompatibility. However, most of the methods used to produce the porous metal can only give limited porosity and uncontrollable pore morphologies. In the present study, a newly developed method of powder metallurgy using the space-holder technique was used to fabricate porous titanium with controllable porosity. The morphological features and mechanical properties of the products were fully investigated. The results show that the porosity is in the range of 55%-75%, and the mean pore size, with an average sphericity of -0.72, is 600 μm. The plateau stresses vary between 10 MPa and 35 MPa. As predicted by the Gibson-Ashby model, the plateau stress decreases with increasing porosity.
基金financially supported by the National Natural Science Foundation of China (No. 51771101)
文摘The infiltration casting fabrication process based on spherical CaCl_(2) space-holders and the compressive behavior including the mechanical performance and energy absorption capacity of open-cell aluminum foams were investigated.Open-cell aluminum foams with different porosities in the range of 63.1%to 87.3%can be fabricated by adjusting compression ratios of CaCl_(2) preforms prepared by precision hot-pressing.The compression tests show that a strain-hardening phenomenon always occurs especially for open-cell aluminum foam with low porosity,resulting in the inclining stress-strain curve in the plateau region.The energy absorption capacity of open-cell aluminum foam decreases with increasing porosity when compared at the same strain.However,when compared at a given stress,each foam can absorb the maximal energy among the five foams in a special stress range.Additionally,open-cell aluminum foam possesses the maximum energy absorption efficiency at its optimum operating stress.At this stress condition,the foam can absorb the highest energy compared with other foams at the same stress point.The optimum operating stress and the corresponding maximal energy absorption decrease with increasing the porosity.The optimum operating stress for energy absorption can also be determined similarly when taking into consideration of the lightweight extent of foams.
文摘In the present work,a compressible and lubricating space-holder material commonly known as "acrawax" was used to process Cu foams with various pore sizes and various porosities.The foams were processed without using binders to avoid contamination of their metal matrices.The lubricant space-holder material was found to facilitate more uniform flow and distribution of metal powder around the surface of the space holder.In addition,the use of acrawax as a space-holder material yielded considerably dense cell walls,which are an essential prerequisite for better material properties.The foams processed with a smaller-sized space holder were found to exhibit better electrical and mechanical properties than those processed with a coarser-sized space holder.The isotropic pore shape,uniform pore distribution throughout the metal matrix,and uniform cell wall thickness were found to enhance the properties pertaining to fine-pore foam samples.The processed foams exhibit properties similar to those of the foams processed through the lost-carbonate sintering process.
基金supported by the Korea Research Foundation (KRF)
文摘Titanium and its alloys are currently considered as one of the most important metallic materials used in the biomedical applications, due to their excellent mechanical properties and superior biocompatibility. In the present study, a new effective method for fabricating high porosity titanium alloy scaffolds was developed. Porous Ti-6Al-4V scaffolds are successfully fabricated with porosities ranging from 30% to 70% using spaceholder and powder sintering technique. Based on its acceptable properties, spherical carbamide particles with different diameters （0.56, 0.8, and 1mm） were used as the space-holder material in the present investigation. The Ti-6Al-4V scaffolds porosity is characterized by using scanning electron microscopy. The results show that the scaffolds spherical-shaped pores are depending on the shape, size and distribution of the space-holder particles. This investigation shows that the present new manufacturing technique is promising to fabricate a controlled high porosity and high purity Ti-6Al-4V scaffolds for hard tissue replacement.
基金National Natural Science Foundation of China(51761013,51674055)Jiangxi Provincial Education Department Program(GJJ160655)Doctoral Special Research Development Program of Jiangxi University of Science and Technology(jxxjbs16019)
基金Supported by NSFC(No.11671031,No.11471018)the Fundamental Research Funds for the Central Universities(No.FRF-TP-14-005C1)+1 种基金Program for New Century Excellent Talents in Universitythe Beijing Natural Science Foundation(No.1142005)
