β-Fe2O3·H2O is prepared by reacting FeCl3, K2CO3, an oxidizing agent HIO4 and a metal chelating agent K3PO4 at 65~ 70℃. The prepared β-Fe2O3' H2O is introduced into the mixture of KOH, KOCl and a ferrate s...β-Fe2O3·H2O is prepared by reacting FeCl3, K2CO3, an oxidizing agent HIO4 and a metal chelating agent K3PO4 at 65~ 70℃. The prepared β-Fe2O3' H2O is introduced into the mixture of KOH, KOCl and a ferrate stabilizer KI, and reacted at room temperature for 5 h to produce a ferrate-containing cake. The cake is dried to give a water-free dried potassium ferrate (VI).展开更多
研究了钨含量为36%,Ni与Fe质量比为7/3和9/1的两种W Ni Fe三元合金的预应变时效硬度变化规律,用X射线衍射鉴定了时效后两种合金的物相组成,并用透射电镜观察其微观结构。结果表明:Ni与Fe质量比为7/3的W Ni Fe三元合金在800℃下进行预应...研究了钨含量为36%,Ni与Fe质量比为7/3和9/1的两种W Ni Fe三元合金的预应变时效硬度变化规律,用X射线衍射鉴定了时效后两种合金的物相组成,并用透射电镜观察其微观结构。结果表明:Ni与Fe质量比为7/3的W Ni Fe三元合金在800℃下进行预应变时效时,硬度随时间增加而单调降低;相同条件下Ni与Fe质量比为9/1的W Ni Fe三元合金时效初期硬度下降,但随时间延长硬度又逐步提高。X射线衍射物相鉴定和透射电子显微分析发现:Ni与Fe质量比为7/3的合金在预应变时效过程中没有明显沉淀析出物,其时效硬度下降是固溶度降低、残余应力消除以及回复与再结晶的结果;而Ni与Fe质量比为9/1的合金经预应变时效后析出了细小弥散的β相,其硬度变化存在两种机制,一种是固溶度降低、残余应力消除和回复与再结晶引起软化,另一种是细小β相沉淀析出导致弥散强化。展开更多
The effects of Sr,Mg,Cr,Sr/Mg and Sr/Cr combined additions on the Fe-containing intermetallic phase in a recycled Al-Si-Fe cast alloy are investigated.The experimental results show that the additions of Cr and Sr/Cr s...The effects of Sr,Mg,Cr,Sr/Mg and Sr/Cr combined additions on the Fe-containing intermetallic phase in a recycled Al-Si-Fe cast alloy are investigated.The experimental results show that the additions of Cr and Sr/Cr successfully modified the platelet and flake-likeβ-Al-5FeSi phases （β-compound） into the fibrousα-Al-8Fe-2Si （α-compound）.The additions of Sr and Sr/Mg were less effective to modify theβ-compound into theα-compound,while the eutectic Si was fully modified into the fibrous morphology.A small secondary dendrite arm spacing （DAS） was found in the Sr-added,Cr-added and Sr/Cr-added alloys,especially in a steel mold.The Sr,Sr/Cr and Sr/Mg combined additions modify the eutectic Si simultaneously.A sludge phase was found in the addition of Cr-added,Sr/Cr-added and Mg-added alloys,especially in the graphite mold casting.The volume fraction ofβ-compounds was decreased by the addition of various modifying elements. The Cr and Sr/Cr combined additions are very effective to modify theβ-compound for the recycled Al-Si-Fe based alloys.展开更多
The hardness variation of two kinds of alloys with 36 wt pct W content and 7/3, 9/1 Ni-to-Fe ratios during strain aging at 800℃ was studied. The microstructures of the aged alloys were analyzed by X-ray diffraction a...The hardness variation of two kinds of alloys with 36 wt pct W content and 7/3, 9/1 Ni-to-Fe ratios during strain aging at 800℃ was studied. The microstructures of the aged alloys were analyzed by X-ray diffraction and TEM. The results show that the strain aging hardness of W-Ni-Fe ternary alloy with 7/3 Ni-to-Fe ratio decreases monotonically with the increase of aging time. Under the same conditions, the hardness of 9/1 Ni-to-Fe ratio alloy decreases in the initial aging stage, but then increases as aging process goes on. X ray diffraction and TEM analysis show that there is not any precipitation depositing from the alloy with 7/3 Ni-to-Fe ratio during aging. The monotonic decrease in hardness of this alloy during aging process results from the recovery, recrystallization and solid solubility declining. In the alloy of 9/1 Ni-to-Fe ratio, the fine β phase precipitates dispersively during aging which hardens the alloy. The two different kinds of mechanisms (the softening one and the hardening one) decide the hardness variation of the alloy with 9/1 Ni-to-Fe ratio mentioned above.展开更多
文摘β-Fe2O3·H2O is prepared by reacting FeCl3, K2CO3, an oxidizing agent HIO4 and a metal chelating agent K3PO4 at 65~ 70℃. The prepared β-Fe2O3' H2O is introduced into the mixture of KOH, KOCl and a ferrate stabilizer KI, and reacted at room temperature for 5 h to produce a ferrate-containing cake. The cake is dried to give a water-free dried potassium ferrate (VI).
文摘研究了钨含量为36%,Ni与Fe质量比为7/3和9/1的两种W Ni Fe三元合金的预应变时效硬度变化规律,用X射线衍射鉴定了时效后两种合金的物相组成,并用透射电镜观察其微观结构。结果表明:Ni与Fe质量比为7/3的W Ni Fe三元合金在800℃下进行预应变时效时,硬度随时间增加而单调降低;相同条件下Ni与Fe质量比为9/1的W Ni Fe三元合金时效初期硬度下降,但随时间延长硬度又逐步提高。X射线衍射物相鉴定和透射电子显微分析发现:Ni与Fe质量比为7/3的合金在预应变时效过程中没有明显沉淀析出物,其时效硬度下降是固溶度降低、残余应力消除以及回复与再结晶的结果;而Ni与Fe质量比为9/1的合金经预应变时效后析出了细小弥散的β相,其硬度变化存在两种机制,一种是固溶度降低、残余应力消除和回复与再结晶引起软化,另一种是细小β相沉淀析出导致弥散强化。
文摘The effects of Sr,Mg,Cr,Sr/Mg and Sr/Cr combined additions on the Fe-containing intermetallic phase in a recycled Al-Si-Fe cast alloy are investigated.The experimental results show that the additions of Cr and Sr/Cr successfully modified the platelet and flake-likeβ-Al-5FeSi phases （β-compound） into the fibrousα-Al-8Fe-2Si （α-compound）.The additions of Sr and Sr/Mg were less effective to modify theβ-compound into theα-compound,while the eutectic Si was fully modified into the fibrous morphology.A small secondary dendrite arm spacing （DAS） was found in the Sr-added,Cr-added and Sr/Cr-added alloys,especially in a steel mold.The Sr,Sr/Cr and Sr/Mg combined additions modify the eutectic Si simultaneously.A sludge phase was found in the addition of Cr-added,Sr/Cr-added and Mg-added alloys,especially in the graphite mold casting.The volume fraction ofβ-compounds was decreased by the addition of various modifying elements. The Cr and Sr/Cr combined additions are very effective to modify theβ-compound for the recycled Al-Si-Fe based alloys.
基金This work was supported by the National Natural Science Foundation of China under grant No.59971007.
文摘The hardness variation of two kinds of alloys with 36 wt pct W content and 7/3, 9/1 Ni-to-Fe ratios during strain aging at 800℃ was studied. The microstructures of the aged alloys were analyzed by X-ray diffraction and TEM. The results show that the strain aging hardness of W-Ni-Fe ternary alloy with 7/3 Ni-to-Fe ratio decreases monotonically with the increase of aging time. Under the same conditions, the hardness of 9/1 Ni-to-Fe ratio alloy decreases in the initial aging stage, but then increases as aging process goes on. X ray diffraction and TEM analysis show that there is not any precipitation depositing from the alloy with 7/3 Ni-to-Fe ratio during aging. The monotonic decrease in hardness of this alloy during aging process results from the recovery, recrystallization and solid solubility declining. In the alloy of 9/1 Ni-to-Fe ratio, the fine β phase precipitates dispersively during aging which hardens the alloy. The two different kinds of mechanisms (the softening one and the hardening one) decide the hardness variation of the alloy with 9/1 Ni-to-Fe ratio mentioned above.
