Thermal resistance of low-melting-temperature alloy(LMTA) thermal interface materials(TIMs) was measured by laser flash method before and after different stages of heating.The results showed that the thermal performan...Thermal resistance of low-melting-temperature alloy(LMTA) thermal interface materials(TIMs) was measured by laser flash method before and after different stages of heating.The results showed that the thermal performance of the LMTA TIMs was degraded during the heating process.It is suggested that the degradation may mainly be attributed to the interfacial reaction between the Cu and the molten LMTAs.Due to the fast growth rate of intermetallic compound(IMC) at the solid–liquid interface,a thick brittle IMC is layer formed at the interface,which makes cracks easy to initiate and expand.Otherwise,the losses of indium and tin contents in the LMTA during the interfacial reaction will make the melting point of the TIM layer increase,and so,the TIM layer will not melt at the operating temperature.展开更多
Alloying structural steel used for mechanical structures has a high requirement for cleanliness because its failures are greatly affected by non-metallic inclusions and total oxygen content in steel.It has been report...Alloying structural steel used for mechanical structures has a high requirement for cleanliness because its failures are greatly affected by non-metallic inclusions and total oxygen content in steel.It has been reported by some steelmaking plants to have some problems in controlling total oxygen content and inclusions during alloying structural steel production.For this purpose,cleanliness control in 0.2C-0.3Si-0.6Mn-1Cr-0.2Mo steel was investigated.Firstly,low melting temperature zone(≤1873 K) of CaO-Al2O3-MgO system and formation condition of low melting temperature inclusions were investigated through thermodynamic equilibrium calculation.On this basis,industrial tests were carried out.Through sampling at different stages,transformation of oxide inclusions and change of total oxygen content in steel were studied.The results show that:in order to form CaO-Al2O3-MgO system inclusions with low melting temperature,mass percent of Al2O3,MgO and CaO in inclusions should be controlled from 37.6% to 70.8%,0 to 17.4% and 25.5% to 60.6%;For the condition of 1873 K and 0.05%(mass percent) dissolved aluminum in steel,the activities of dissolved oxygen,magnesium and calcium should be controlled as 0.298×10-4-2×10-4,0.1×10-5-40×10-5 and 0.8×10-8-180×10-8 respectively.With secondary refining proceeding,average total oxygen content and inclusion amount decrease,the type of most inclusions changes from Al2O3 after tapping to Al2O3-MgO after top slag is formed during ladle furnace refining and finally to CaO-Al2O3-MgO after RH treatment.In the final products,average total oxygen content was 12.7×10-6 and most inclusions were in spherical shape with size less than 5 μm.展开更多
Polyphenylene sulfides(PPS) and low-melting temperature glasses(LMTG) were used to prepare a PPS/LMTG organicinorganic hybrid material by melt blending.The etched surfaces of the hybrids were observed by scanning elec...Polyphenylene sulfides(PPS) and low-melting temperature glasses(LMTG) were used to prepare a PPS/LMTG organicinorganic hybrid material by melt blending.The etched surfaces of the hybrids were observed by scanning electron microscope (SEM) and the images showed different dispersed phase morphologies compared to traditional filled composites,which maybe induced by shear.Advanced rheometric expanded system(ARES) was used to investigate the rheological behaviors of the hybrids and the results showed that the strain y dependence of dynamic storage modulus G' for the hybrids with high contents of LMTG did not appear Payne effect.展开更多
基金supported by the National Basic Research Program of China (No.2010CB631006)the National Natural Science Foundation of China (No.51171191)
文摘Thermal resistance of low-melting-temperature alloy(LMTA) thermal interface materials(TIMs) was measured by laser flash method before and after different stages of heating.The results showed that the thermal performance of the LMTA TIMs was degraded during the heating process.It is suggested that the degradation may mainly be attributed to the interfacial reaction between the Cu and the molten LMTAs.Due to the fast growth rate of intermetallic compound(IMC) at the solid–liquid interface,a thick brittle IMC is layer formed at the interface,which makes cracks easy to initiate and expand.Otherwise,the losses of indium and tin contents in the LMTA during the interfacial reaction will make the melting point of the TIM layer increase,and so,the TIM layer will not melt at the operating temperature.
基金Item Sponsored by National Basic Research Program of China(2010CB630806)
文摘Alloying structural steel used for mechanical structures has a high requirement for cleanliness because its failures are greatly affected by non-metallic inclusions and total oxygen content in steel.It has been reported by some steelmaking plants to have some problems in controlling total oxygen content and inclusions during alloying structural steel production.For this purpose,cleanliness control in 0.2C-0.3Si-0.6Mn-1Cr-0.2Mo steel was investigated.Firstly,low melting temperature zone(≤1873 K) of CaO-Al2O3-MgO system and formation condition of low melting temperature inclusions were investigated through thermodynamic equilibrium calculation.On this basis,industrial tests were carried out.Through sampling at different stages,transformation of oxide inclusions and change of total oxygen content in steel were studied.The results show that:in order to form CaO-Al2O3-MgO system inclusions with low melting temperature,mass percent of Al2O3,MgO and CaO in inclusions should be controlled from 37.6% to 70.8%,0 to 17.4% and 25.5% to 60.6%;For the condition of 1873 K and 0.05%(mass percent) dissolved aluminum in steel,the activities of dissolved oxygen,magnesium and calcium should be controlled as 0.298×10-4-2×10-4,0.1×10-5-40×10-5 and 0.8×10-8-180×10-8 respectively.With secondary refining proceeding,average total oxygen content and inclusion amount decrease,the type of most inclusions changes from Al2O3 after tapping to Al2O3-MgO after top slag is formed during ladle furnace refining and finally to CaO-Al2O3-MgO after RH treatment.In the final products,average total oxygen content was 12.7×10-6 and most inclusions were in spherical shape with size less than 5 μm.
基金supported by the National Natural Science Funds of China(No.51073137)
文摘Polyphenylene sulfides(PPS) and low-melting temperature glasses(LMTG) were used to prepare a PPS/LMTG organicinorganic hybrid material by melt blending.The etched surfaces of the hybrids were observed by scanning electron microscope (SEM) and the images showed different dispersed phase morphologies compared to traditional filled composites,which maybe induced by shear.Advanced rheometric expanded system(ARES) was used to investigate the rheological behaviors of the hybrids and the results showed that the strain y dependence of dynamic storage modulus G' for the hybrids with high contents of LMTG did not appear Payne effect.
