Stability of thermal cycling and high temperature mechanical properties for Ti–V–Al–B lightweight shape memory alloy

The microstructure of the Ti–V–Al shape memory alloy with refined grain and in-situ TiB phase was modified by doping minor Boron (B), which contributes to the superior mechanical performances and strain recovery characteristics. Compared with other quaternary Ti–V–Al-X alloys, the Ti–V–Al–B alloy showed the largest ultimate tensile stress due to the solution strengthening, grain refinement and precipitation strengthening of in-situ TiB phase. Moreover, the Ti–V–Al alloy added 0.1 ?at.%B possessed the maximum yield stress of 701 ?MPa and the largest tensile fracture strain of 27.6% at the temperature of 150 ?°C. Meanwhile, the excellent strain recovery characteristics with fully recoverable strain of 4% could be obtained due to B addition. Besides, B addition suppressed the precipitation of ω phase during thermal cycling and further improved the thermal cycling stability of the Ti–V–Al alloy.     

废聚苯乙烯泡沫塑料综合利用研究进展

聚苯乙烯泡沫具有质量轻、表观密度低、不易分解、廉价等优点，是当下应用最广泛的塑料制品之一。同时其废弃物的丢弃量也越来越大，这种聚苯乙烯泡沫废弃物在大自然中难以降解，燃烧还会产生有毒物质，导致回收处理难度较大，给环境带来了很多问题。如果将废聚苯乙烯泡沫塑料（WFPS）进行回收或者资源化利用，不仅能改善环境问题，而且符合“低碳”理念。对WFPS的回收包括溶剂回收、热解回收等方法进行了详细地介绍，重点综述了WFPS在能源领域、建筑领域和环境保护领域的资源化再利用的研究现状。结合中国WFPS的回收现状对其今后回收与再利用技术研究前景作出了展望：1）兼顾经济与环保的规模化溶剂回收技术的开发；2）催化裂解回收单体的高效催化剂的研发；3）聚焦高附加值的WFPS资源化利用技术研究。     

Na2B4O7添加剂对复合钢管陶瓷衬层组织性能的影响

采用铝热离心法制备了陶瓷内衬钢管，研究了Ｎａ２Ｂ４Ｏ７ 添加剂和过铝量对陶瓷内衬致密度、组织和性能的影响。在自蔓延过程中作为稀释剂存在的Ｎａ２Ｂ４Ｏ７，降低燃烧温度和燃烧速率。添加剂对陶瓷致密化具有双重影响。５％ ～１０ ｗ ｔ％ 添加剂，延长陶瓷层的熔融期，可明显改善陶瓷致密度和内表面光整度。陶瓷层无裂纹和剥皮现象。陶瓷晶粒呈等轴状。随着添加剂量的增加，陶瓷硬度和耐蚀性均稍有下降。陶瓷内衬钢管具有优异的抗热冲击性能。     

Near-microscopic grain boundary facilitates fatigue crack propagation in a polycrystalline Al–Zn–Mg–Cu alloy

In present study, grain characteristics with sizes within 10–30 μm were fabricated from a same Al–Zn–Mg–Cu alloy, FCP behaviors of the alloys with small grain(SG alloy), medium grain(MG alloy) and large grain(LG alloy)were investigated and related fatigue fracture morphology was analyzed. With the enhancement of stress intensity factor range(ΔK), the alloy with larger grains possessed faster FCP rate, which were successively arranged as SG alloy > MG alloy > LG alloy at initial stage while...