Effects of Low Nickel Content on Microstructure and High-Temperature Mechanical Properties of Al-7Si-1.5Cu-0.4Mg Aluminum Alloy

In this paper, the effects of Ni content on the room and elevated temperature (250 °C) tensile strength of Al-7Si-1.5Cu-0.4Mg-0.3Mn-0.1RE-xNi (x = 0, 0.3, 0.6, 0.9 wt.%) alloys were investigated, along with microstructure characterization and tensile testing. In the as-cast state, the dominant Ni-rich phases were primarily the γ-Al7Cu4Ni and δ-Al3CuNi phases. Following the solution heat treatment, a significant reduction in the γ-Al7Cu4Ni phase was noted, accompanied by the emergence of numerous small ε-Al3Ni phases. Both room temperature strength and high temperature strength at 250 °C exhibited a consistent increase with rising Ni content, reaching 405 MPa and 261 MPa, respectively, at 0.9 Ni content, which were increased by 6.4% and 16.8%, respectively, compared with 0 Ni content. The elongation exhibited an oscillating increase within the Ni content range of 0 to 0.6, reaching peak values of 2.6% in room temperature and 4.3% in high temperature at 0.6 Ni, followed by a rapid decline. At 0.6 Ni content, the alloy demonstrated a well-balanced combination of mechanical properties, featuring commendable strength and plasticity

Source of condensate oil in the middle of southern margin, Junggar Basin, NW China

Through detailed geochemical analysis of over 40 crude oil, condensate oil and heavy oil samples in the southern margin of Junggar Basin, and based on the hydrocarbon generation condition of five sets of source rocks, with the combination between compositions of carbon isotopes of whole oil, light hydrocarbon, n-alkanes isoprenoids and biomarker composition characteristics, a detailed discussion on the source of the condensate oil in anticlines in the central part of the southern margin was carried out. Condensate oils from the central part of the southern margin have abundant isoprenoids, Pr/Ph<1.0. Carbon isotopes of whole oil are low with δ13C value between −27‰ and −28‰. The δ13C value of alkanes with carbon number smaller than 9 ranges from −26‰ to −24‰, carbon isotopes of C9+ n-alkanes decrease remarkably with increasing carbon number, and the δ13C value of C19+ n-alkanes is lower than −30‰. The δ13C value of pristane and phytane is lower than −29‰. The biomarker components contain abundant C27 steranes and C30 methyl steranes, “V” shape distribution of C27, C28 and C29 20R sterane, abundant tricyclic terpanes with dominance of C21, and relatively high content of gammacerane with two isomers. The 20S/(20S+20R) ratio of C29 steranes is between 0.40 and 0.50, and the maturity calculated by the methylphenanthrene index and distribution fraction (Rc) ranges from 0.70% to 1.1%. These geochemical characteristics of the condensate oils are very similar to those mature crude oils from the typical Cretaceous lacustrine source rocks in the central part of southern margin, but are greatly different from those of typical Jurassic crude oils, implying that these condensate oils are derived from mature Cretaceous lacustrine source rocks instead of highly mature Jurassic coal-measures source rocks. Key words: condensate oil, oil source, molecular carbon isotope, biomarker, Cretaceous, southern margin of Junggar Basi

Curbing opportunism in logistics outsourcing relationships: The role of relational norms and contract

Logistics outsourcing, as a strategy to obtain competitive advantages, is prevalent in today's business world. However, we know little about logistics outsourcing, especially with regard to opportunistic behavior types and their relational antecedents (e.g., contracts and relational norms) of their opportunism in the third party logistics (3PL) user-provider relationships in emerging economies. Using China's developing 3PL industry as a research context, and social exchange theory and transaction cost economics as the theoretical lenses, we examine how three dimensions of relational norms (information exchange, flexibility, solidarity) influence two dimensions of contracts (detailed contracts, contract application), and how relational norms and contracts simultaneously influence 3PL providers’ opportunism. Using data collected from 247 manufacturing and service firms in China, we empirically test the proposed model and find that detailed contracts and solidarity are effective safeguards in reducing 3PL providers’ opportunistic behavior, while the contract application process leads to opportunism. Furthermore, flexibility is positively related to detailed contracts and the contract application process, which can influence 3PL providers’ opportunism negatively and positively, respectively. This study contributes to the logistics outsourcing, opportunism, and relationship management literature and provides managerial implications for 3PL practices in China